IP Scanner is a cloud tool that scans your local network and returns a sortable list of the devices it discovers. Devices can be filtered, searched, and exported to CSV. By default, it detects and scans a local subnet, though you can also define a custom IP range. Mac Network Scanner. On the Mac, you have a couple of options. LanScan is a free app on the Mac Store that does a very simple scan and displays the IP address, MAC address, Hostname and Vendor. The free version will only list the first four hostnames fully and the rest will only show the first three characters. Use MAC Address Scanner (free trial) to scan subnets and create tables relating IP addresses to MAC addresses, DNSs, and manufacturer addresses. Search for MAC addresses on your network and more with the 60-plus network management and troubleshooting tools in SolarWinds Engineers Toolset. Advanced IP Scanner. Reliable and free network scanner to analyse LAN. The program shows all network devices, gives you access to shared folders, provides remote control of computers (via RDP and Radmin), and can even remotely switch computers off. It is easy to use and runs as a portable edition. It should be the first choice for every network.
Amid predictions that 75.44 billion devices will have internet connectivity by 2025, IP address management has become a fundamental housekeeping and security concern for any networking admin. As the Internet of Things (IoT) continues to endow more and more devices with smart capabilities, networking grows more complex, making IP-centered network security measures a business imperative. With more devices comes more risk of networking complications and potential breachesespecially given the BYOD (Bring Your Own Device) trend, which allows employees to connect to company Wi-Fi via their personal mobile phones and laptops.
To maintain good network health and prevent unauthorized users from spying or wasting valuable bandwidth, admins are expected to not only know how to scan their network for devices but also understand the importance behind IP address management.
With the number of networked devices skyrocketing, network administrators must know how to scan their network for devices, track IP addresses, and perform IP address management. This guide describes how IP address scanners help empower IT departments to better track the many devices within a network, identify when IP addresses have been mislabeled or misallocated, and detect possible breaches, in addition to diving deeper into the why and how of IP address management from answering basic to advanced IP address strategies.
Positioning Your Organization for Success
How to Find All IP Addresses on a Network
Knowing how to scan the network for devices is the first step, and one of the most fundamental, in managing IP addresses. When organizational members experience problems connecting their device to the network or the internet, having a full list of IP addresses on the network can guide administrators as they troubleshoot and restore order.
The most basic way to find all the IP addresses on a network is with a manual network scan. This method is best for those looking to perform a rapid, one-time device check or for those heading smaller organizations with a more manageable device list. To rapidly scan a network yourself using native operating system (OS) capabilities, follow these steps.
Open the command prompt.
Enter the command ipconfig for Mac or ifconfig on Linux. Your computer will then display its own IP address, subnet mask, gateway address, and more, making it possible for you to determine the network number youll be scanning. For example, in a Class C IPv4 networkwhich most small local networks are wont to beyou may find your computers IP address is, lets say, 192.168.1.75. If the subnet mask is 255.255.255.0, then you know the first 3 bytes are the network ID (192.168.1) and your broadcast IP address is 192.168.1.255.
Next, input the command arp -a. ARP stands for Address Resolution Protocol, and the -a appendage of the command prompts the device to list all the IP addresses found within the ARP cache for the associated network. In other words, the arp -a command displays all active IP addresses connected to the local network. This list is incredibly informative, containing the IP addresses, MAC addresses, and allocation type (whether static or dynamic) for all live hosts.
Optional: Input the command ping -t. The ping -t command allows you to perform an extended ping on the list produced by the previous command, testing connectivity and latency within the network. This will enable you to further narrow down what devices could be experiencing or causing problems.
However, there are a few ways to scan local networks for IP addresses. Typically, the best way to find the IP addresses of all devices on a network is to invest in software. This is especially true for large organizations using dynamic IP addresses, in which case the large volume of networked devices and staggered address changes can quickly become overwhelming to track and organize. Using an IP address scanner, admins can see which addresses are active, which are free for reallocation, which might belong to unauthorized users, and which have perhaps been duplicated and caused collisions. Best IP Scanners
While its possible to scan a network for active IP addresses using native commands, manually tracking the addresses of all networked devices can quickly become an outsized task for any one staff member. This is particularly true when you look at the data this method makes available to you. Yes, ipconfig displays the IP address of each active network device and its corresponding MAC address, but most IT members dont happen to know the MAC address of every single computer within the networkthat expectation would be unreasonable, if not impossible in larger networks. Suffice it to say, this information doesnt exactly guide you to the root source of a problem or provide much network mapping. It merely enables you to identify IP addresses and spot possible duplicates or mismatches.
For this reason, downloading software with a fuller suite of IP address management (IPAM) services is highly recommended. To help you fill out your IPAM toolset, Ive rounded up the seven best network scanner and address management clients. While some are free, these are generally more supplementary tools. Cobbled together, a collection of standalone software can certainly yield powerful results.
In terms of expedient and comprehensive data consolidation, however, the best results tend to come from premium software. A completely integrated management toollike the SolarWinds IP Address Manager, the most robust IPAM software and my personal favoritemight have a higher price tag but ultimately pays for itself by automating rote tasks and performing insightful analysis, decreasing system downtime while increasing productivity and profit.
With that said, Ill review free tools first before delving into full-service clients. 1. IP Address Tracker (Free)
By far the most powerful tool on the list of free clients, SolarWinds IP Address Tracker is a standalone solution, available for free download, that works on its own but is further enhanced by the SolarWinds IPAM suite when integrated. This makes it an excellent first step if youre considering a premium option but looking for a fully functional address tracker in the meantime.
For a free tool, SolarWinds IP Address Tracker is extraordinary: not only does it allow users to manage up to 254 IP addresses, but it automatically pushes alerts when IP address conflicts occur. Whats more, it creates a repository of all IP addresses on a network, tracks subnets, and shows which addresses are available.
Finally, its graphical user interface displays information in an intuitive and digestible format, highlighting notable events while remaining comprehensive in nature. For example, it shows a list of custom reports, the last 25 IPAM events, current conflicts, and ranked subnets by the percentage of available addresses used. 2. Angry IP Scanner (Free)
Widely hailed as one of the first and most popular free IP address scanners, Angry IP Scanner is open-source software, deployable across operating systems. Windows, Linux, and Mac OS X users will find this tool handy for its nonexistent price tag.
Angry IP Scanner is easy to use and has an intuitive graphical user interface. Further, it provides slightly more detail than the manual command-line method covered above. Given an IP address range, the tool displays all active IP addresses, hostname when applicable, ping response time, MAC address, and port count. These results are made actionable with an export function that supports CSV, TXT, XML, and IP-Port list files.
Additionally, Angry IP Scanner can display Network Basic Input/Output System (NetBIOS) information useful for identifying an IP address, as knowing the computer name or current logged-in user can facilitate network problem solving.
The main downside of Angry IP Scanner is the basic nature of its capabilities, which is understandable given that its open-source. The functionalities it offers are fundamental and useful. Plus, anyone who writes Java is free to expand its abilities by creating their own plugins, though of course this would require a certain amount of buy-in. 3. IP Scanner (Free)
Created by developer 10base-t Interactive and optimized for Mac, this app is admittedly limited; the free version only supports 6 devices. Still, for small home networks, this number may be sufficient, and, as a taste of what could be possible with the expanded capacity of the Pro version, IP Scanner offers features many other free apps dont have.
Perhaps most interesting is IP Scanners cumulative mode feature, which allows the user to track network changes over time. In this mode, network admins can see inactive devices that were once part of the network. This can help with troubleshooting in a variety of ways. Is this IP address now free for reallocation? Is this device supposed to be present, and something has gone wrong? IP Scanner takes some of the guesswork out of network fluctuations, making it possible to zero in on these questions and find answers.
Another intelligent feature is the tools whitelist capability, which allows users to filter out trusted devices. By culling the display in this way, users can stay aware of which devices are new and may be on the network without authorization, receiving automatic alerts to potential threats. 4. IP Address Manager
The preeminent full-service IP address management tool, SolarWinds IPAM goes far beyond the offerings of an IP address tracker. In addition to all the SolarWinds IP Address Tracker features covered above, IPAM is a complete management solution, empowering admins to drill down into address conflicts, easily allocate IP addresses to subnets, and catalogue IP address usage history.
These functions are crucial time-savers. When alerted to a conflict, users can begin troubleshooting by viewing the events details, including the specific endpoints involved. This allows admins to temporarily remove the malfunctioning devices by remotely shutting down a port, thus facilitating network reliability and high performance while reconfiguring IP settings behind the conflict.
As regards address allocation, IPAM users can employ the automated Subnet Discovery Wizard and Subnet Allocation Wizard to sort IP addresses and form optimally sized subnets, maximizing performance while minimizing conflicts and wasted space. Better yet, IPAM features drag-and-drop and user-defined grouping, making portioning IP address space more convenient than ever before.
One last notable feature here is that it offers priceless server synchronization. This makes it possible not merely to set alerts for conflicts and put out fires as they arise, but to prevent potentially expensive address conflicts to begin with. IPAM integrates DNS server and DHCP server management in one console and supports multiple vendors. This means customers can find available addresses, assign them, and update the DNS simultaneously, eliminating the possibility of misdirected traffic or duplication. 5. Engineers Toolset
Next up is SolarWinds Engineers Toolset (ETS), a bundle of over 60 tools designed to discover, configure, monitor, and troubleshoot your network. This includes a slate of tools fulfilling the duties of an IP tracker or scanner, bolstered by myriad others in this holistic network management client.
Some of the toolsets key strengths are its convenience and birds-eye-view perspective of complex enterprise networks. SolarWinds ETS performs automated network discovery, allowing it to undertake clear network visualizationa capability not found in most free tools. With the automated discovery, the toolset displays the network in its entirety, mapping out switch ports, relating MAC to IP addresses, and identifying equipment.
To this end, ETS generates powerfully informative graphics for all IPAM concerns. Not only does the Ping Sweep tool provide a quick rundown of which addresses are in use and which are available for assignment, but it also locates the DNS name corresponding to each IP address. It supplements this data with graphs charting device response time.
Beyond scanning and mapping networks, Engineers Toolset makes reconfiguring the network for optimal performance a breeze. The Subnet Calculator at once scans subnets; generates the proper masks, size, range, and broadcast address of both classful and classless subnets; and acts as an IP address tracker, continuously monitoring the addresses in use within each subnet.
The DHCP Scope Monitor, meanwhile, monitors DHCP servers to push alerts when certain scopes are low on addresses and quantifies the number of dynamic IP addresses within the network. This is an incredibly important function when re-architecting a network or trying to avoid downtime, as it gauges whether the network is due to run out of addresses before a verifiable shortage arrives.
Further, the DNS Audit tool maximizes IP address efficiency through its ability to run forward and reverse DNS lookups to find any misalignment with host addresses and DNS records. This helps ensure if a device is using an IP address, the network reaps the rewards of having allocated that address.
Coupled with the innumerable other amenities of SolarWinds ETS, its network scanning and IP address tracking features go even further in preventing network catastrophe, identifying problems early, ascertaining root causes, and executing quick resolutions. 6. Network Performance Monitor
SolarWinds Network Performance Monitor (NPM) is another fully loaded toolkit ready to scan networks for devices. Its network device scanner tool automatically discovers network devices; beyond that, NPM creates visual displays that delineate the connections between devices automatically populating maps that clarify network topology. This is particularly helpful in the case of the dynamic IP address system, in which IP addresses (in addition to device count and relationship) are constantly in flux.
Network visualization in NPM goes far beyond the typical features of an IPAM tool. In fact, with SolarWinds NPM, users can customize dynamic network maps that display accurate topology and device performance metrics, juxtaposing device scanning and network performance management so that admins can more easily architect high-performing networks and intervene on specific devices when necessary. 7. User Device Tracker
SolarWinds User Device Tracker (UDT) performs an IP address management role from a unique vantage point, looking more at the individual user in addition to network architecture. UDT is invaluable when it comes to granular network topology and equipment details. It automatically discovers and monitors layer 2 and layer 3 switches, and it constantly watches ports and switches, gauging response time, packet loss, CPU load, and memory utilization. It sends alerts as switches approach their capacity.
UDT serves a pragmatic function in this way through network visualization and performance monitoring. In addition, it provides enhanced visibility into network users and strengthens network securityan increasingly crucial consideration as networks grow more complex and organizational members each bring a bevy of devices, presenting more opportunities for breaches.
With SolarWinds UDT, admins can not only customize their own reportsvital for compliancebut they can also drill into device connection history and user login history. Most importantly, they can cut through the noise to identify any unauthorized users siphoning resources from their network or, worse, carrying out cyberattacks. The UDT whitelisting feature empowers admins to designate safe, known devices so it can push alerts when new and potentially dangerous devices come online. The Importance of IP Addresses in Networking
Now that you have the best tool in place to scan, monitor, and manage IP addresses on your network, having a baseline understanding of how IP addresses workincluding the differences between the addressing systems of IPv4 and IPv6can also help protect the performance and integrity of networks. Lets go into deeper detail about what exactly an IP address is, types of IP addresses, and how to assign IP addresses to devices. What Is an IP?
The IP address exists to identify devices connecting via the internet, which is itself a network of other networks communicating via the standards delineated by the Transfer Control Protocol (TCP) and Internet Protocol (IP). The term internet in this sense is different than Local Area Networks (LANs) in that its decentralizedmeaning no specific person or device has administrative privileges to impose controls on the weband allows each internet-connected device to act independently online.
To achieve internet access, then, every device must have a way of identifying itself. Identification serves two primary purposes:
It acts as a return address so all packets transmitted over TCP (all data transfers and communication exchanges, basically) can be verified.
It allows other devices to find and communicate with the device in question.
Though accessing the internet quickly and easily is something most take for granted, its a process comprised of multiple steps. A user who wishes to reach a site on a computer or other device inputs the domain name (like www.dnsstuff.com) into their browser, which then contacts its designated domain name system (DNS) server to resolve the URL to an IP address. Once the device has the IP address, it can connect to the site and interact however it wants.
Because most networks, including LANs, virtual LANs, and Wide Area Networks (WANs), use the TCP/IP protocol suite to connect the devices in a given organization or location, the IP address system works similarly to ensure network devices can successfully send data to one another.
All IP addresses have both binary and dot-decimal notations for an address. The binary representation of an IP address is used to communicate with devices, while the translated dotted decimal format helps make it easier for users to understand and remember IP addresses. What Version Is My IP Address? IPv4 vs. IPv6
Currently, there are two coexisting standards (also called versions) for formulating IP addresses:
In IPv4 (Internet Protocol version 4), an IP address is made up of decimal digits and contains 32 bits or 4 bytes. Each byte constitutes an 8-bit field with decimals and a period, which is why some call IPv4 address nomenclature the dot-decimal format.
While this has worked well enough for quite some time, the 32-bit constraint means IPv4 only allows for variations or approximately 4 billion addresses. At present, the global number of internet-connected devices already far exceeds that threshold, at 26.66 billion. To compensate, many networks use both private and public IP addresses, so several devices within a local network may share a public IP address but have separate private IP addresses. A system called the Dynamic Host Configuration Protocol (DHCP) assigns private IP addresses within a network.
While this system has worked historically, it poses a couple of problems. First, it introduces an additional step in networking and increases administrative overhead. Second, if the DHCP and DNS server arent synchronized (or if multiple DHCPs are running at once, which admins should avoid), listed IP addresses can be incorrect or duplicated, causing transfer issues that can, in turn, hinder network performance. When two devices share a single IP address, they may not be able to connect to the internet or the local network at all.
IPv6 was developed to circumvent these complications. Four times larger than an IPv4 address, an IPv6 address contains 128 bits in total, written in hexadecimal, and punctuated by colons rather than periods.
With more data allocated for each address, the IPv6 protocol creates many more IP address variations than IPv4, eliminating the need to assign public and private addresses, which can result in collisions. Since it allows for variations, the new protocol provides a good deal of room for IoT to grow.
Because IPv6 is an evolutionary upgrade, it can coexist with IPv4 and will do so until the earlier version is eventually phased out. For this reason, IPv6 is also referred to as IPng meaning Internet Protocol next generation.
So far, IPv6 addresses still represent the minority of internet traffic, but theyve started to capture a larger portion. As of June 2019, around 29 of Google users accessed the site over IPv6, and around 38 of internet users in the United States have already adopted IPv6 with minimal latency rates. By transitioning to IPv6 over time, the internet should be able to allocate more individual addresses to devices, increasing both the number of hosts and the volume of data traffic it can accommodate. What Is IPv4?
Each IPv4 address contains two crucial components: a network identifier and a host identifier. In this way, its much like a geographic addressthe street gives people an idea of the neighborhood where a building is located, and the number isolates the building in question.
In an IPv4 address, the network identifier contains the network number, which, per its name, identifies the specific network to which the device belongs. The host identifier, or node identifier, is the collection of bits unique to the device in use on the network, differentiating it from other machines on the network and on the internet. IPv4 Classful Addressing Basics
The number of nodes a network will need to support determines the exact structure of the IPv4 address, which is further classified into different address classes.
Class A IPv4 addresses If the first bit of an IPv4 binary address is 0, then the address is a Class A type. Class A is typically used in large organizations as it can generate millions of unique node variations. Class A has an IP address range of 0.0.0.0 127.255.255.255
Class B IPv4 addresses If the first two bits are 10, the IPv4 address is Class B. Class B can produce tens of thousands of node address variants and is primarily used in medium-sized networks. Class B has an IP range of 128.0.0.0 191.255.255.255
Class C IPv4 addresses All Class C addresses start with 110. Since Class C IPv4 address allocates one byte to the host identifier, this tier of IPv4 network can only support a maximum of 254 hosts. This is because a byte of data is equal to 8 bits, or 8 binary digits. With a bit limited to representing either 0 or 1, an 8-bit piece of data allows for a maximum of (256) variations. However, the host identifier 0 is reserved for the IP address designated to the network, and 255 belongs to the IP address designated to the broadcast address, leaving 254 network nodes for other devices. Class C has an IP range of 192.0.0.0 223.255.255.255
While Classes D and E also exist, Class D is used exclusively for multicasts and Class E not available to the general public. Classful vs. Classless Addressing
Because of fears that the classful IPv4 addressing system was too quickly using up available address variations, the Internet Engineering Task Force developed the Classless Inter-Domain Routing (CIDR) system to allow for network prefixes sized between the 8-bit intervals instituted by classful networking. With CIDR, an IPv4 address doesnt have a set composition defined by its class; it can, however, have a prefix (the portion specifying the network number or subnet ID) of arbitrary length. The size of this prefix determines the number of variations available to each network or subnetwork. Show Ip Addresses On Network
CIDR can work because of the variable-length subnet masking (VLSM) technique. Put simply, the subnet mask expresses in dot-decimal IP form how many bits in the IPv4 address belong to the prefix. For example, a CIDR with a prefix length of 4 (meaning the network number is only 4 bits, as opposed to a typical Class A length of 8) is, in binary, 11110000 00000000 00000000 00000000. The byte 11110000 numerically translates to 240, making this subnet mask address 240.0.0.0. Given this subnet mask, an admin knows the network can support devicesmuch more than a Class A IPv4 address.
According to CIDR notation, the length of the subnet mask (the number of bits used by the prefix) is expressed by a suffix composed of a slash and a number. So, given the IP address 192.168.1.0/24, a user would know the following:
The prefix is 24 bits, or 3 bytes, in length, making it a Class C IP address
Therefore, the network can support up to 254 devices
The network address is the first 3 blocks, or 192.168.1
The IP address is 11111111 11111111 11111111 00000000 in binary, translating to the subnet mask 255.255.255.0 What Is IPv6?
IPv6 addresses work in a similar fashion to IPv4 addresses, though they contain more data. Each hexadecimal number requires 4 bits, and each block consists of 4 hexadecimals. Each IPv6 address contains 8 blocks128 bits total, which are, like IPv4, divided into network and node components. The difference between the two versions is IPv6 addresses dont vary in composition; the network and node components are always of equal length, at 64 bits each.
The first 64 bits correspond to the network component, laying out the global unicast address (48 bits) followed by the subnet ID (16 bits). Essentially, this means that the first 3 bytes identify the network address used by internet routing to reach the proper network, and the fourth byte (configured by network administrators themselves) routes any communications to the correct internal subnet within the broader local network.
The last 64 bits make up the interface ID, which identifies the node within the network that internal network or external internet communications must reach. The interface ID is generated from the media access control (MAC) address, given by network interface card manufacturers and stored in the device hardware.
Although IPv6 addresses dont have classes, the hexadecimals with which the address starts can inflect what type of network it is. Global addresses starting with 2001 are public, whereas link-local addresses starting with fe80 and unique local addresses starting with fc00::/8 or fd00::/8 can channel communications internally, but not over the internet.
Ultimately, IPv6 incurs some inconveniences. Namely, infrastructure will have to transition between the protocol versions, and the addresses are significantly longer. But the protocol solves the most notable dilemma networking faces: a shortage of IP addresses.
With its expanded capacity to support network nodes, IPv6 doesnt just offer enough addresses for now; indeed, it is equipped to generate more variations than well (hopefully) ever need. The number is practically inconceivable in human terms. As one computer hobbyist puts it, that value (340,282,366,920,938,463,463,374,607,431,768,211,456) is equal to over 340 undecillion. Put another way, that amounts to 50 octillion IP addresses per human being, given a global population of 7.5 billion. How to Assign IP Addresses
Finally, to round out our understanding, its worth clarifying how IP addresses are assigned to devices, and how this can affect network operation. There are two basic forms of IP address: static and dynamic.
In a static system, an administrator assigns the IP address and it doesnt change with server updates, router reboots, or website changes. This understandably has its pros and cons. A static IP address can be relied upon to stay the same regardless of other infrastructure developments, meaning IT admins will never encounter a surprise when scanning for IP addresses. However, depending on the size of the network, the manual allocation of all host IP addresses can require a massive amount of time, tracking, and structuring. Especially given that static addresses can become incompatible with a system in various ways, choosing to exclusively use static addresses is largely inefficient and inflexible.
Nevertheless, there are several good reasons to opt for the static IP address system. The process of assigning a static IP address is lengthy and complicated, so it typically requires a professional. This constraint makes static IP addresses more suitable to a business environment, though they can add benefits to home networks as well. Static IP addresses are helpful when:
You want to ensure a shared resource (like a printer or server) is always accessible to everyone on the network, no matter their device, by giving it an unchanging address
You want to use devices incompatible with DHCP
You want to avoid IP address duplications, which a faulty DHCP server can generate
You want slightly improved network security and geolocation precision compared to a dynamic IP address system
Dynamic IP addresses, in contrast, are assigned by the DHCP server, eliminating the need for an admin to spend hours allocating addresses. As their name implies, dynamic IP addresses dont stay the same over timethe DHCP doles out IP addresses to devices on a temporary lease. This automates many of the more irksome details of configuring an IP address system: without administrative oversight, the DHCP server can assign a unique IP address, a subnet mask, a gateway address, and other requisite reference information (like the address of the DNS server) to all devices.
The advantages of the DHCP system are obvious: it reduces administrative overhead and scales with the environment. It has its disadvantages, as well, notably regarding the temporary nature of the dynamic IP address. Although the network client can attempt to renew the same address repeatedly, its address is not guaranteed. Particularly when it comes to remote work, attempts to gain access to a distant device or network can fail without knowledge of its current IP address.
Additionally, within networks primarily reliant on DHCP but have defined a few static IP addresses for isolated devices, a DHCP server can generate a unique IP address that conflicts with an existing static one, or the DNS and DHCP servers can fall out of sync, causing some sites and devices to become unreachable. These potential hiccups have solutionsaltering the DHCP scope to exclude static addresses in use; changing DNS scavenging settings to ensure the server purges old records and updates its databut they require foresight and additional work.
Still, barring slight complications, a dynamic IP address system is the most reasonable solution for large-scale networks. While many enterprises may use a static IP address with their router for remote networking or internet security purposes, DHCP is an efficient, useful system for node address designation overall. Positioning Your Organization for Success
Overall, regardless of network size, downloading tools can offset an IT departments workload. While free tools are adept at handling smaller taskslike simply discovering active IP addresses and correlating them to MAC addressesa diverse toolkit like those offered by SolarWinds IP Address Manager provides a comprehensive solution.
Whether youre maintaining the security of a small network or looking to manage networks at the enterprise scale, the premium IP address management solutions from SolarWinds add the most value of any tool on the market. By performing data analysis, streamlining high volumes of data into insightful graphs, offering useful network visualization, and pushing security and IP address conflict alerts, SolarWinds software can help ensure networks remain in safe, peak-performance shape. Ultimately, through keeping tabs on the many rote and time-intensive tasks required by IP address systems, these robust tools free up administrators to apply themselves elsewhere.
Scanning for IP address lets you have better control over your network. With 1-2 commands, you can quickly map out the devices in your network and the IP addresses that they are using. But to understand how to scan a network, first, you need to understand how are IP addresses assigned. DHCP (Assigning IPs Dynamically)
An automated process in networking, called DHCP (Dynamic Host Configuration Protocol), assigns IP dynamic addresses to hosts as soon as they enter the network. In a home or small network, the DHCP server is usually a part of the router. When you come into the network, the router will look for an available IP address in its pool and assign it to you, so that your device can communicate with others without any conflict.
Dynamic allocation of IP addresses is a great advantage for both end-users and network admins. But sometimes you would need to have some control in order to manage and troubleshoot your network more efficiently. What will you learn in this Tutorial
In this tutorial, you will learn the basic networking skills on how to scan a network for IP addresses. We will scan a network with native OS commands, find which addresses were assigned dynamically, which statically, and test their connectivity.
In the end, we will compare some IP address scanning tools that can give you additional information. To improve your IP addressing insights, even more, we will show you some tools that allow you to track IP addresses and even manage them. Simple IP Scanning
Operating Systems, like Windows and Linux, come with their own native simple networking set of tools. Commands such as ipconfig, arp -a, or ping allow simple scanning and troubleshooting.
The simplest way to get a quick list of IP addresses and their devices connected to your network is with those OS native commands found in the command line. With a list of the assigned IP address and their devices, you can easily find the devices that are causing the most problems.
ipconfig
This command displays all network settings assigned to one or all adapters in the computer. You can find information such as your own IP, subnet, and Gateway. For Linux and MacOS is Ifconfig.
arp -a
When you issue the arp -a, youll get IP-address-to-mac conversion and the allocation type (whether dynamic or static) of all devices in your network.
Ping
It helps determine connectivity between two hosts and find the IP address of a hostname. Reading The Output Finding your own network adapter configuration
In the following screenshot, youll see the output from the ipconfig command. On a Windows, the ipconfig command can be entered through the Command line.
Go to Run type cmd type ipconfig
This Windows computer has 5 network adapters, but the last one (Wireless LAN adapter Wi-Fi) is the only one connected to a network. The rest are disconnected.
In this network, the router (or Default Gateway) is playing the role of the DHCP server. It is assigning the IP address dynamically and giving access to the Internet.
You are reading two of the most important IP addresses for your device; Your own devices IP (IPv4 and IPv6) and your Gateway. The Subnet Mask is also very important, it shows that you are on the same subnet as the gateway.
Now you know your subnet, which in this case is 192.168.1.0/24 (using the CIDR range). Now you need to find the rest of the IP address in your network. Scanning your Network
The job of the ARP protocol is to map IPs to MAC addresses. It provides a method for hosts on a LAN to communicate without knowing any address and create a cache of information. When a new computer enters the LAN, it receives an IP and updates its ARP cache with the Gateway information. This ARP cache can be found using the arp-a command.
Use the command line to enter the arp -a command.
This computer has been connected for some time into the LAN, so its ARP cache is very precise and complete. The first IP address shown in the display is the Gateway (the same we found through the ipconfig command).
The output shows the IP, the MAC addresses, and their assignation type. The addresses displayed here were dynamically assigned by the DHCP server in the LAN. All of these IPs are devices connected to the LAN (192.168.1.0/24). The other static addresses are reserved for Multicasting.
With the MAC information, you can know the vendor. Try searching for vendor prefixes or use an automatic online tool such as MACvendors. Testing Connectivity
Finally, with some information, you can test connectivity. In the following test, we tried an extended ping with ping -t to the gateway. With this, you can learn some simple insights about delay and latency.
From the list generated by the ARP command, you could ping all the live hosts. Or you can go beyond and ping the entire subnet to find hosts not found by the ARP (but that would be too much manual work). Later, well discuss how to automatically ping entire subnets at once.
Although having a list of devices and their allocated IP address will give you good insights, the information will not be enough when your network scales. Manual IP scanning in multiple subnets and BYOD (Bring-Your-Own-Device) scenarios is nearly impossible. As the network scales, problems will scale too.
Larger networks demand more results, flexibility, and easy-to-read set of commands.
An IP Address Scanner tool helps you with larger demands. These tools are able to map the entire local network, finds live hosts, and to provide the results of the arp-a in a clearer format. Other IP Scanners do not depend on ARP but they operate using repeated ping tests. A Ping Sweep tool lets you ping entire subnets and find live hosts just with one button.
Some other IP Scanners go the extra mile and give more information such as Port number, DNS, DHCP, etc. All of this data is also presented in the most visual and easy-to-read format. They also allow users to save all results and present them in detailed reports. Advanced IP Scanners 1. Angry IP Scanner
Angry IP Scanner is one of the most popular scanners on the web, with over 29 million downloads. It is open-source, free, and available for Windows, MacOS, and Linux. It can let you scan your local network or the Internet-facing IP addresses.
This tool is not only capable of scanning IP addresses but also ports. When you define an IP address range, you can also specify a number of the port, and see if a device in your network is using a specific service (defined by the port). Angry IP Scanner also lets you save all the scan results into multiple formats, such as TXT, XML, CVS, etc.
When you scan, youll know what hosts are alive, their response time, hostname, MAC address, etc. If you want even more information, you can extend results by developing Java plugins.
Price:
Open Source and 100 free.
Download:
Get Angry IP from its official site. 2. SolarWinds Ping Sweep
Ping Sweep from SolarWinds helps you find free IPs and identify which ones are unavailable. It is classified as a networking discovery tool from the SolarWinds Engineers Toolset. A comprehensive network software, that includes over 60 handy tools. Ping Sweep from SolarWinds is included in the Engineers Toolset and is dedicated for ping testing. For the MAC address, port scans, SNMP scans, etc, there are more dedicated tools in the Engineers Toolset.
Just as when you ping from the command line, this tool shows the DNS name for each IP and response time. It can also let you export results in different formats such as CSV, TXT, XLS, and to an HTML page.
Price:
SolarWinds Engineers Toolset starts at $1,380.00 and includes over 60 must-have tools.
Download:
Get a fully functional Engineers Toolset for 14 days by registering to SolarWinds official site.
IP Address Tracker Tools
Having a map of IP addresses, MAC addresses, used ports, etc, is great for networking inventorying and may help with some troubleshooting cases. But a list can not control and display real-time results.
An IP address Tracker is a good upgrade to our set of tools and commands described so far. It does allow scanning multiple subnets and displaying results, but it also allows you to keep track of one or more IP addresses. Scan For Ip Addresses On Network Cmd
An IP Address Tracker will notice when an IP address is released. This can be either because the device lost connectivity or it changed IP address. It will help you minimize IP addressing conflicts (when two devices are trying to take the same IP) and reduce DNS errors. 3. MyLAN Viewer
MyLAN Viewer is a NetBIOS and IP address scanner for Windows systems. Just like the IP Scanners shown above, this tool will scan a network and show devices in an easy-to-read format.
But MyLANViewer goes beyond, and not only shows computer name, IP, and MAC, but also NIC, OS version, logged users, shared folders, and much more.
This tool is able to track specific IP addresses and show notifications when their state change. With it, you can also keep track of network security by showing port information and detecting rogue DHCP servers. MyLAN Viewer tracks all devices in the subnet including hidden, and displays alerts when new devices enter the network, and others go.
This tool can also display the following metrics as well:
Display Whois data.
Perform traceroute.
Manage Remote Shutdown and Wake On LAN (WOL).
Monitor wireless networks.
Price:
Free, but only available for Windows systems.
Download:
Get MyLAN Viewer from its official site. 4. SolarWinds IP Tracker
SolarWinds IP Tracker is a standalone software and completely free. In addition to creating inventories of all devices, this tool allows you to scan, track, and manage IP address, including their event logs, all in a single place. SolarWinds IP Tracker is the free version and feature-limited of the much coveted IP Address Manager.
But the IP Tracker does an amazing job to provide a centralized view of the entire IP addressing scheme. It lets you monitor 256 (one subnet) IP addresses for free. Additionally, this tool allows basic management functionalities with tools such as, Ping, Telnet, Traceroute. The best of all is that, with SolarWinds IP Tracker you can detect IP address conflicts created by misconfigured DHCP servers.
SolarWinds IP Tracker is only supported by Windows systems.
Price:
100 Free.
Download:
Register in SolarWinds to download the software for free.
IP Address Management (IPAM)
Basic IP Address Scanning should be enough to manage small networks. But when networks scale they depend on multiple subnets and detailed management requirements. Although SolarWinds IP Tracker is able to find IP address conflicts, it is not able to control them.
Sometimes large-scale networks have standalone DHCP and DNS Servers in order to assign addresses to multiple subnets. But IP conflicts occur and it is really challenging to manage them manually. An IP Address Management or IPAM is a piece of software able to actively control DHCP and DNS. It also gives you the ability to manage multiple subnets. 5. SolarWinds IP Address Scanner
Among SolarWinds powerful tools, the IP Address Manager does everything a large-scale enterprise needs to manage its addresses properly. It automates many processes to make IP Address management easier. From automated IP address tracking, quick static IP reservations, to multi-vendor DHCP and DNS support.
SolarWinds IPAM comes with an integrated IP address management, DHCP, and DNS tools to administer your entire network.
One of the most commonly used tools from this bundle is the IP Address Scanner. This tool allows you to create automated IP address scans to maintain an updated inventory of all IP address blocks in the network. This is achieved by sending regular ICMP and SNMP polls. The automatic scans use ICMP polls to gather status of the IP address and hostname information. It also uses SNMP to find information on MAC addresses and other vendor information. SolarWinds IP Address Scanner supports both IPv4 and IPv6 address management. Angry Ip Scanner Mac Address
SolarWinds IPAM also provides detailed reports of your IP address in real-time.
Price:
Download the Free Trial for 30 Days!
Download: Scan My Network For Ip Addresses Mac Os
Get a fully functional SolarWinds IPAM for 30 days by registering to SolarWinds official site.
Amid predictions that 75.44 billion devices will have internet connectivity by 2025, IP address management has become a fundamental housekeeping and security concern for any networking admin. As the Internet of Things (IoT) continues to endow more and more devices with smart capabilities, networking grows more complex, making IP-centered network security measures a business imperative. With more devices comes more risk of networking complications and potential breachesespecially given the BYOD (Bring Your Own Device) trend, which allows employees to connect to company Wi-Fi via their personal mobile phones and laptops.
To maintain good network health and prevent unauthorized users from spying or wasting valuable bandwidth, admins are expected to not only know how to scan their network for devices but also understand the importance behind IP address management.
With the number of networked devices skyrocketing, network administrators must know how to scan their network for devices, track IP addresses, and perform IP address management. This guide describes how IP address scanners help empower IT departments to better track the many devices within a network, identify when IP addresses have been mislabeled or misallocated, and detect possible breaches, in addition to diving deeper into the why and how of IP address management from answering basic to advanced IP address strategies.
Positioning Your Organization for Success
How to Find All IP Addresses on a Network
Knowing how to scan the network for devices is the first step, and one of the most fundamental, in managing IP addresses. When organizational members experience problems connecting their device to the network or the internet, having a full list of IP addresses on the network can guide administrators as they troubleshoot and restore order.
The most basic way to find all the IP addresses on a network is with a manual network scan. This method is best for those looking to perform a rapid, one-time device check or for those heading smaller organizations with a more manageable device list. To rapidly scan a network yourself using native operating system (OS) capabilities, follow these steps.
Open the command prompt.
Enter the command ipconfig for Mac or ifconfig on Linux. Your computer will then display its own IP address, subnet mask, gateway address, and more, making it possible for you to determine the network number youll be scanning. For example, in a Class C IPv4 networkwhich most small local networks are wont to beyou may find your computers IP address is, lets say, 192.168.1.75. If the subnet mask is 255.255.255.0, then you know the first 3 bytes are the network ID (192.168.1) and your broadcast IP address is 192.168.1.255.
Next, input the command arp -a. ARP stands for Address Resolution Protocol, and the -a appendage of the command prompts the device to list all the IP addresses found within the ARP cache for the associated network. In other words, the arp -a command displays all active IP addresses connected to the local network. This list is incredibly informative, containing the IP addresses, MAC addresses, and allocation type (whether static or dynamic) for all live hosts.
Optional: Input the command ping -t. The ping -t command allows you to perform an extended ping on the list produced by the previous command, testing connectivity and latency within the network. This will enable you to further narrow down what devices could be experiencing or causing problems.
However, there are a few ways to scan local networks for IP addresses. Typically, the best way to find the IP addresses of all devices on a network is to invest in software. This is especially true for large organizations using dynamic IP addresses, in which case the large volume of networked devices and staggered address changes can quickly become overwhelming to track and organize. Using an IP address scanner, admins can see which addresses are active, which are free for reallocation, which might belong to unauthorized users, and which have perhaps been duplicated and caused collisions. Best IP Scanners
While its possible to scan a network for active IP addresses using native commands, manually tracking the addresses of all networked devices can quickly become an outsized task for any one staff member. This is particularly true when you look at the data this method makes available to you. Yes, ipconfig displays the IP address of each active network device and its corresponding MAC address, but most IT members dont happen to know the MAC address of every single computer within the networkthat expectation would be unreasonable, if not impossible in larger networks. Suffice it to say, this information doesnt exactly guide you to the root source of a problem or provide much network mapping. It merely enables you to identify IP addresses and spot possible duplicates or mismatches.
For this reason, downloading software with a fuller suite of IP address management (IPAM) services is highly recommended. To help you fill out your IPAM toolset, Ive rounded up the seven best network scanner and address management clients. While some are free, these are generally more supplementary tools. Cobbled together, a collection of standalone software can certainly yield powerful results.
In terms of expedient and comprehensive data consolidation, however, the best results tend to come from premium software. A completely integrated management toollike the SolarWinds IP Address Manager, the most robust IPAM software and my personal favoritemight have a higher price tag but ultimately pays for itself by automating rote tasks and performing insightful analysis, decreasing system downtime while increasing productivity and profit.
With that said, Ill review free tools first before delving into full-service clients. 1. IP Address Tracker (Free)
By far the most powerful tool on the list of free clients, SolarWinds IP Address Tracker is a standalone solution, available for free download, that works on its own but is further enhanced by the SolarWinds IPAM suite when integrated. This makes it an excellent first step if youre considering a premium option but looking for a fully functional address tracker in the meantime.
For a free tool, SolarWinds IP Address Tracker is extraordinary: not only does it allow users to manage up to 254 IP addresses, but it automatically pushes alerts when IP address conflicts occur. Whats more, it creates a repository of all IP addresses on a network, tracks subnets, and shows which addresses are available.
Finally, its graphical user interface displays information in an intuitive and digestible format, highlighting notable events while remaining comprehensive in nature. For example, it shows a list of custom reports, the last 25 IPAM events, current conflicts, and ranked subnets by the percentage of available addresses used. 2. Angry IP Scanner (Free)
Widely hailed as one of the first and most popular free IP address scanners, Angry IP Scanner is open-source software, deployable across operating systems. Windows, Linux, and Mac OS X users will find this tool handy for its nonexistent price tag.
Angry IP Scanner is easy to use and has an intuitive graphical user interface. Further, it provides slightly more detail than the manual command-line method covered above. Given an IP address range, the tool displays all active IP addresses, hostname when applicable, ping response time, MAC address, and port count. These results are made actionable with an export function that supports CSV, TXT, XML, and IP-Port list files.
Additionally, Angry IP Scanner can display Network Basic Input/Output System (NetBIOS) information useful for identifying an IP address, as knowing the computer name or current logged-in user can facilitate network problem solving.
The main downside of Angry IP Scanner is the basic nature of its capabilities, which is understandable given that its open-source. The functionalities it offers are fundamental and useful. Plus, anyone who writes Java is free to expand its abilities by creating their own plugins, though of course this would require a certain amount of buy-in. 3. IP Scanner (Free)
Created by developer 10base-t Interactive and optimized for Mac, this app is admittedly limited; the free version only supports 6 devices. Still, for small home networks, this number may be sufficient, and, as a taste of what could be possible with the expanded capacity of the Pro version, IP Scanner offers features many other free apps dont have.
Perhaps most interesting is IP Scanners cumulative mode feature, which allows the user to track network changes over time. In this mode, network admins can see inactive devices that were once part of the network. This can help with troubleshooting in a variety of ways. Is this IP address now free for reallocation? Is this device supposed to be present, and something has gone wrong? IP Scanner takes some of the guesswork out of network fluctuations, making it possible to zero in on these questions and find answers.
Another intelligent feature is the tools whitelist capability, which allows users to filter out trusted devices. By culling the display in this way, users can stay aware of which devices are new and may be on the network without authorization, receiving automatic alerts to potential threats. 4. IP Address Manager
The preeminent full-service IP address management tool, SolarWinds IPAM goes far beyond the offerings of an IP address tracker. In addition to all the SolarWinds IP Address Tracker features covered above, IPAM is a complete management solution, empowering admins to drill down into address conflicts, easily allocate IP addresses to subnets, and catalogue IP address usage history.
These functions are crucial time-savers. When alerted to a conflict, users can begin troubleshooting by viewing the events details, including the specific endpoints involved. This allows admins to temporarily remove the malfunctioning devices by remotely shutting down a port, thus facilitating network reliability and high performance while reconfiguring IP settings behind the conflict.
As regards address allocation, IPAM users can employ the automated Subnet Discovery Wizard and Subnet Allocation Wizard to sort IP addresses and form optimally sized subnets, maximizing performance while minimizing conflicts and wasted space. Better yet, IPAM features drag-and-drop and user-defined grouping, making portioning IP address space more convenient than ever before.
One last notable feature here is that it offers priceless server synchronization. This makes it possible not merely to set alerts for conflicts and put out fires as they arise, but to prevent potentially expensive address conflicts to begin with. IPAM integrates DNS server and DHCP server management in one console and supports multiple vendors. This means customers can find available addresses, assign them, and update the DNS simultaneously, eliminating the possibility of misdirected traffic or duplication. 5. Engineers Toolset
Next up is SolarWinds Engineers Toolset (ETS), a bundle of over 60 tools designed to discover, configure, monitor, and troubleshoot your network. This includes a slate of tools fulfilling the duties of an IP tracker or scanner, bolstered by myriad others in this holistic network management client.
Some of the toolsets key strengths are its convenience and birds-eye-view perspective of complex enterprise networks. SolarWinds ETS performs automated network discovery, allowing it to undertake clear network visualizationa capability not found in most free tools. With the automated discovery, the toolset displays the network in its entirety, mapping out switch ports, relating MAC to IP addresses, and identifying equipment.
To this end, ETS generates powerfully informative graphics for all IPAM concerns. Not only does the Ping Sweep tool provide a quick rundown of which addresses are in use and which are available for assignment, but it also locates the DNS name corresponding to each IP address. It supplements this data with graphs charting device response time.
Beyond scanning and mapping networks, Engineers Toolset makes reconfiguring the network for optimal performance a breeze. The Subnet Calculator at once scans subnets; generates the proper masks, size, range, and broadcast address of both classful and classless subnets; and acts as an IP address tracker, continuously monitoring the addresses in use within each subnet.
The DHCP Scope Monitor, meanwhile, monitors DHCP servers to push alerts when certain scopes are low on addresses and quantifies the number of dynamic IP addresses within the network. This is an incredibly important function when re-architecting a network or trying to avoid downtime, as it gauges whether the network is due to run out of addresses before a verifiable shortage arrives.
Further, the DNS Audit tool maximizes IP address efficiency through its ability to run forward and reverse DNS lookups to find any misalignment with host addresses and DNS records. This helps ensure if a device is using an IP address, the network reaps the rewards of having allocated that address.
Coupled with the innumerable other amenities of SolarWinds ETS, its network scanning and IP address tracking features go even further in preventing network catastrophe, identifying problems early, ascertaining root causes, and executing quick resolutions. 6. Network Performance Monitor
SolarWinds Network Performance Monitor (NPM) is another fully loaded toolkit ready to scan networks for devices. Its network device scanner tool automatically discovers network devices; beyond that, NPM creates visual displays that delineate the connections between devices automatically populating maps that clarify network topology. This is particularly helpful in the case of the dynamic IP address system, in which IP addresses (in addition to device count and relationship) are constantly in flux.
Network visualization in NPM goes far beyond the typical features of an IPAM tool. In fact, with SolarWinds NPM, users can customize dynamic network maps that display accurate topology and device performance metrics, juxtaposing device scanning and network performance management so that admins can more easily architect high-performing networks and intervene on specific devices when necessary. 7. User Device Tracker
SolarWinds User Device Tracker (UDT) performs an IP address management role from a unique vantage point, looking more at the individual user in addition to network architecture. UDT is invaluable when it comes to granular network topology and equipment details. It automatically discovers and monitors layer 2 and layer 3 switches, and it constantly watches ports and switches, gauging response time, packet loss, CPU load, and memory utilization. It sends alerts as switches approach their capacity.
UDT serves a pragmatic function in this way through network visualization and performance monitoring. In addition, it provides enhanced visibility into network users and strengthens network securityan increasingly crucial consideration as networks grow more complex and organizational members each bring a bevy of devices, presenting more opportunities for breaches.
With SolarWinds UDT, admins can not only customize their own reportsvital for compliancebut they can also drill into device connection history and user login history. Most importantly, they can cut through the noise to identify any unauthorized users siphoning resources from their network or, worse, carrying out cyberattacks. The UDT whitelisting feature empowers admins to designate safe, known devices so it can push alerts when new and potentially dangerous devices come online. The Importance of IP Addresses in Networking
Now that you have the best tool in place to scan, monitor, and manage IP addresses on your network, having a baseline understanding of how IP addresses workincluding the differences between the addressing systems of IPv4 and IPv6can also help protect the performance and integrity of networks. Lets go into deeper detail about what exactly an IP address is, types of IP addresses, and how to assign IP addresses to devices. What Is an IP?
The IP address exists to identify devices connecting via the internet, which is itself a network of other networks communicating via the standards delineated by the Transfer Control Protocol (TCP) and Internet Protocol (IP). The term internet in this sense is different than Local Area Networks (LANs) in that its decentralizedmeaning no specific person or device has administrative privileges to impose controls on the weband allows each internet-connected device to act independently online.
To achieve internet access, then, every device must have a way of identifying itself. Identification serves two primary purposes:
It acts as a return address so all packets transmitted over TCP (all data transfers and communication exchanges, basically) can be verified.
It allows other devices to find and communicate with the device in question.
Though accessing the internet quickly and easily is something most take for granted, its a process comprised of multiple steps. A user who wishes to reach a site on a computer or other device inputs the domain name (like www.dnsstuff.com) into their browser, which then contacts its designated domain name system (DNS) server to resolve the URL to an IP address. Once the device has the IP address, it can connect to the site and interact however it wants.
Because most networks, including LANs, virtual LANs, and Wide Area Networks (WANs), use the TCP/IP protocol suite to connect the devices in a given organization or location, the IP address system works similarly to ensure network devices can successfully send data to one another.
All IP addresses have both binary and dot-decimal notations for an address. The binary representation of an IP address is used to communicate with devices, while the translated dotted decimal format helps make it easier for users to understand and remember IP addresses. What Version Is My IP Address? IPv4 vs. IPv6
Currently, there are two coexisting standards (also called versions) for formulating IP addresses:
In IPv4 (Internet Protocol version 4), an IP address is made up of decimal digits and contains 32 bits or 4 bytes. Each byte constitutes an 8-bit field with decimals and a period, which is why some call IPv4 address nomenclature the dot-decimal format.
While this has worked well enough for quite some time, the 32-bit constraint means IPv4 only allows for variations or approximately 4 billion addresses. At present, the global number of internet-connected devices already far exceeds that threshold, at 26.66 billion. To compensate, many networks use both private and public IP addresses, so several devices within a local network may share a public IP address but have separate private IP addresses. A system called the Dynamic Host Configuration Protocol (DHCP) assigns private IP addresses within a network.
While this system has worked historically, it poses a couple of problems. First, it introduces an additional step in networking and increases administrative overhead. Second, if the DHCP and DNS server arent synchronized (or if multiple DHCPs are running at once, which admins should avoid), listed IP addresses can be incorrect or duplicated, causing transfer issues that can, in turn, hinder network performance. When two devices share a single IP address, they may not be able to connect to the internet or the local network at all.
IPv6 was developed to circumvent these complications. Four times larger than an IPv4 address, an IPv6 address contains 128 bits in total, written in hexadecimal, and punctuated by colons rather than periods.
With more data allocated for each address, the IPv6 protocol creates many more IP address variations than IPv4, eliminating the need to assign public and private addresses, which can result in collisions. Since it allows for variations, the new protocol provides a good deal of room for IoT to grow.
Because IPv6 is an evolutionary upgrade, it can coexist with IPv4 and will do so until the earlier version is eventually phased out. For this reason, IPv6 is also referred to as IPng meaning Internet Protocol next generation.
So far, IPv6 addresses still represent the minority of internet traffic, but theyve started to capture a larger portion. As of June 2019, around 29 of Google users accessed the site over IPv6, and around 38 of internet users in the United States have already adopted IPv6 with minimal latency rates. By transitioning to IPv6 over time, the internet should be able to allocate more individual addresses to devices, increasing both the number of hosts and the volume of data traffic it can accommodate. What Is IPv4?
Each IPv4 address contains two crucial components: a network identifier and a host identifier. In this way, its much like a geographic addressthe street gives people an idea of the neighborhood where a building is located, and the number isolates the building in question.
In an IPv4 address, the network identifier contains the network number, which, per its name, identifies the specific network to which the device belongs. The host identifier, or node identifier, is the collection of bits unique to the device in use on the network, differentiating it from other machines on the network and on the internet. IPv4 Classful Addressing Basics
The number of nodes a network will need to support determines the exact structure of the IPv4 address, which is further classified into different address classes.
Class A IPv4 addresses If the first bit of an IPv4 binary address is 0, then the address is a Class A type. Class A is typically used in large organizations as it can generate millions of unique node variations. Class A has an IP address range of 0.0.0.0 127.255.255.255
Class B IPv4 addresses If the first two bits are 10, the IPv4 address is Class B. Class B can produce tens of thousands of node address variants and is primarily used in medium-sized networks. Class B has an IP range of 128.0.0.0 191.255.255.255
Class C IPv4 addresses All Class C addresses start with 110. Since Class C IPv4 address allocates one byte to the host identifier, this tier of IPv4 network can only support a maximum of 254 hosts. This is because a byte of data is equal to 8 bits, or 8 binary digits. With a bit limited to representing either 0 or 1, an 8-bit piece of data allows for a maximum of (256) variations. However, the host identifier 0 is reserved for the IP address designated to the network, and 255 belongs to the IP address designated to the broadcast address, leaving 254 network nodes for other devices. Class C has an IP range of 192.0.0.0 223.255.255.255
While Classes D and E also exist, Class D is used exclusively for multicasts and Class E not available to the general public. Classful vs. Classless Addressing
Because of fears that the classful IPv4 addressing system was too quickly using up available address variations, the Internet Engineering Task Force developed the Classless Inter-Domain Routing (CIDR) system to allow for network prefixes sized between the 8-bit intervals instituted by classful networking. With CIDR, an IPv4 address doesnt have a set composition defined by its class; it can, however, have a prefix (the portion specifying the network number or subnet ID) of arbitrary length. The size of this prefix determines the number of variations available to each network or subnetwork. Show Ip Addresses On Network
CIDR can work because of the variable-length subnet masking (VLSM) technique. Put simply, the subnet mask expresses in dot-decimal IP form how many bits in the IPv4 address belong to the prefix. For example, a CIDR with a prefix length of 4 (meaning the network number is only 4 bits, as opposed to a typical Class A length of 8) is, in binary, 11110000 00000000 00000000 00000000. The byte 11110000 numerically translates to 240, making this subnet mask address 240.0.0.0. Given this subnet mask, an admin knows the network can support devicesmuch more than a Class A IPv4 address.
According to CIDR notation, the length of the subnet mask (the number of bits used by the prefix) is expressed by a suffix composed of a slash and a number. So, given the IP address 192.168.1.0/24, a user would know the following:
The prefix is 24 bits, or 3 bytes, in length, making it a Class C IP address
Therefore, the network can support up to 254 devices
The network address is the first 3 blocks, or 192.168.1
The IP address is 11111111 11111111 11111111 00000000 in binary, translating to the subnet mask 255.255.255.0 What Is IPv6?
IPv6 addresses work in a similar fashion to IPv4 addresses, though they contain more data. Each hexadecimal number requires 4 bits, and each block consists of 4 hexadecimals. Each IPv6 address contains 8 blocks128 bits total, which are, like IPv4, divided into network and node components. The difference between the two versions is IPv6 addresses dont vary in composition; the network and node components are always of equal length, at 64 bits each.
The first 64 bits correspond to the network component, laying out the global unicast address (48 bits) followed by the subnet ID (16 bits). Essentially, this means that the first 3 bytes identify the network address used by internet routing to reach the proper network, and the fourth byte (configured by network administrators themselves) routes any communications to the correct internal subnet within the broader local network.
The last 64 bits make up the interface ID, which identifies the node within the network that internal network or external internet communications must reach. The interface ID is generated from the media access control (MAC) address, given by network interface card manufacturers and stored in the device hardware.
Although IPv6 addresses dont have classes, the hexadecimals with which the address starts can inflect what type of network it is. Global addresses starting with 2001 are public, whereas link-local addresses starting with fe80 and unique local addresses starting with fc00::/8 or fd00::/8 can channel communications internally, but not over the internet.
Ultimately, IPv6 incurs some inconveniences. Namely, infrastructure will have to transition between the protocol versions, and the addresses are significantly longer. But the protocol solves the most notable dilemma networking faces: a shortage of IP addresses.
With its expanded capacity to support network nodes, IPv6 doesnt just offer enough addresses for now; indeed, it is equipped to generate more variations than well (hopefully) ever need. The number is practically inconceivable in human terms. As one computer hobbyist puts it, that value (340,282,366,920,938,463,463,374,607,431,768,211,456) is equal to over 340 undecillion. Put another way, that amounts to 50 octillion IP addresses per human being, given a global population of 7.5 billion. How to Assign IP Addresses
Finally, to round out our understanding, its worth clarifying how IP addresses are assigned to devices, and how this can affect network operation. There are two basic forms of IP address: static and dynamic.
In a static system, an administrator assigns the IP address and it doesnt change with server updates, router reboots, or website changes. This understandably has its pros and cons. A static IP address can be relied upon to stay the same regardless of other infrastructure developments, meaning IT admins will never encounter a surprise when scanning for IP addresses. However, depending on the size of the network, the manual allocation of all host IP addresses can require a massive amount of time, tracking, and structuring. Especially given that static addresses can become incompatible with a system in various ways, choosing to exclusively use static addresses is largely inefficient and inflexible.
Nevertheless, there are several good reasons to opt for the static IP address system. The process of assigning a static IP address is lengthy and complicated, so it typically requires a professional. This constraint makes static IP addresses more suitable to a business environment, though they can add benefits to home networks as well. Static IP addresses are helpful when:
You want to ensure a shared resource (like a printer or server) is always accessible to everyone on the network, no matter their device, by giving it an unchanging address
You want to use devices incompatible with DHCP
You want to avoid IP address duplications, which a faulty DHCP server can generate
You want slightly improved network security and geolocation precision compared to a dynamic IP address system
Dynamic IP addresses, in contrast, are assigned by the DHCP server, eliminating the need for an admin to spend hours allocating addresses. As their name implies, dynamic IP addresses dont stay the same over timethe DHCP doles out IP addresses to devices on a temporary lease. This automates many of the more irksome details of configuring an IP address system: without administrative oversight, the DHCP server can assign a unique IP address, a subnet mask, a gateway address, and other requisite reference information (like the address of the DNS server) to all devices.
The advantages of the DHCP system are obvious: it reduces administrative overhead and scales with the environment. It has its disadvantages, as well, notably regarding the temporary nature of the dynamic IP address. Although the network client can attempt to renew the same address repeatedly, its address is not guaranteed. Particularly when it comes to remote work, attempts to gain access to a distant device or network can fail without knowledge of its current IP address.
Additionally, within networks primarily reliant on DHCP but have defined a few static IP addresses for isolated devices, a DHCP server can generate a unique IP address that conflicts with an existing static one, or the DNS and DHCP servers can fall out of sync, causing some sites and devices to become unreachable. These potential hiccups have solutionsaltering the DHCP scope to exclude static addresses in use; changing DNS scavenging settings to ensure the server purges old records and updates its databut they require foresight and additional work.
Still, barring slight complications, a dynamic IP address system is the most reasonable solution for large-scale networks. While many enterprises may use a static IP address with their router for remote networking or internet security purposes, DHCP is an efficient, useful system for node address designation overall. Positioning Your Organization for Success
Overall, regardless of network size, downloading tools can offset an IT departments workload. While free tools are adept at handling smaller taskslike simply discovering active IP addresses and correlating them to MAC addressesa diverse toolkit like those offered by SolarWinds IP Address Manager provides a comprehensive solution.
Whether youre maintaining the security of a small network or looking to manage networks at the enterprise scale, the premium IP address management solutions from SolarWinds add the most value of any tool on the market. By performing data analysis, streamlining high volumes of data into insightful graphs, offering useful network visualization, and pushing security and IP address conflict alerts, SolarWinds software can help ensure networks remain in safe, peak-performance shape. Ultimately, through keeping tabs on the many rote and time-intensive tasks required by IP address systems, these robust tools free up administrators to apply themselves elsewhere.
Scanning for IP address lets you have better control over your network. With 1-2 commands, you can quickly map out the devices in your network and the IP addresses that they are using. But to understand how to scan a network, first, you need to understand how are IP addresses assigned. DHCP (Assigning IPs Dynamically)
An automated process in networking, called DHCP (Dynamic Host Configuration Protocol), assigns IP dynamic addresses to hosts as soon as they enter the network. In a home or small network, the DHCP server is usually a part of the router. When you come into the network, the router will look for an available IP address in its pool and assign it to you, so that your device can communicate with others without any conflict.
Dynamic allocation of IP addresses is a great advantage for both end-users and network admins. But sometimes you would need to have some control in order to manage and troubleshoot your network more efficiently. What will you learn in this Tutorial
In this tutorial, you will learn the basic networking skills on how to scan a network for IP addresses. We will scan a network with native OS commands, find which addresses were assigned dynamically, which statically, and test their connectivity.
In the end, we will compare some IP address scanning tools that can give you additional information. To improve your IP addressing insights, even more, we will show you some tools that allow you to track IP addresses and even manage them. Simple IP Scanning
Operating Systems, like Windows and Linux, come with their own native simple networking set of tools. Commands such as ipconfig, arp -a, or ping allow simple scanning and troubleshooting.
The simplest way to get a quick list of IP addresses and their devices connected to your network is with those OS native commands found in the command line. With a list of the assigned IP address and their devices, you can easily find the devices that are causing the most problems.
ipconfig
This command displays all network settings assigned to one or all adapters in the computer. You can find information such as your own IP, subnet, and Gateway. For Linux and MacOS is Ifconfig.
arp -a
When you issue the arp -a, youll get IP-address-to-mac conversion and the allocation type (whether dynamic or static) of all devices in your network.
Ping
It helps determine connectivity between two hosts and find the IP address of a hostname. Reading The Output Finding your own network adapter configuration
In the following screenshot, youll see the output from the ipconfig command. On a Windows, the ipconfig command can be entered through the Command line.
Go to Run type cmd type ipconfig
This Windows computer has 5 network adapters, but the last one (Wireless LAN adapter Wi-Fi) is the only one connected to a network. The rest are disconnected.
In this network, the router (or Default Gateway) is playing the role of the DHCP server. It is assigning the IP address dynamically and giving access to the Internet.
You are reading two of the most important IP addresses for your device; Your own devices IP (IPv4 and IPv6) and your Gateway. The Subnet Mask is also very important, it shows that you are on the same subnet as the gateway.
Now you know your subnet, which in this case is 192.168.1.0/24 (using the CIDR range). Now you need to find the rest of the IP address in your network. Scanning your Network
The job of the ARP protocol is to map IPs to MAC addresses. It provides a method for hosts on a LAN to communicate without knowing any address and create a cache of information. When a new computer enters the LAN, it receives an IP and updates its ARP cache with the Gateway information. This ARP cache can be found using the arp-a command.
Use the command line to enter the arp -a command.
This computer has been connected for some time into the LAN, so its ARP cache is very precise and complete. The first IP address shown in the display is the Gateway (the same we found through the ipconfig command).
The output shows the IP, the MAC addresses, and their assignation type. The addresses displayed here were dynamically assigned by the DHCP server in the LAN. All of these IPs are devices connected to the LAN (192.168.1.0/24). The other static addresses are reserved for Multicasting.
With the MAC information, you can know the vendor. Try searching for vendor prefixes or use an automatic online tool such as MACvendors. Testing Connectivity
Finally, with some information, you can test connectivity. In the following test, we tried an extended ping with ping -t to the gateway. With this, you can learn some simple insights about delay and latency.
From the list generated by the ARP command, you could ping all the live hosts. Or you can go beyond and ping the entire subnet to find hosts not found by the ARP (but that would be too much manual work). Later, well discuss how to automatically ping entire subnets at once.
Although having a list of devices and their allocated IP address will give you good insights, the information will not be enough when your network scales. Manual IP scanning in multiple subnets and BYOD (Bring-Your-Own-Device) scenarios is nearly impossible. As the network scales, problems will scale too.
Larger networks demand more results, flexibility, and easy-to-read set of commands.
An IP Address Scanner tool helps you with larger demands. These tools are able to map the entire local network, finds live hosts, and to provide the results of the arp-a in a clearer format. Other IP Scanners do not depend on ARP but they operate using repeated ping tests. A Ping Sweep tool lets you ping entire subnets and find live hosts just with one button.
Some other IP Scanners go the extra mile and give more information such as Port number, DNS, DHCP, etc. All of this data is also presented in the most visual and easy-to-read format. They also allow users to save all results and present them in detailed reports. Advanced IP Scanners 1. Angry IP Scanner
Angry IP Scanner is one of the most popular scanners on the web, with over 29 million downloads. It is open-source, free, and available for Windows, MacOS, and Linux. It can let you scan your local network or the Internet-facing IP addresses.
This tool is not only capable of scanning IP addresses but also ports. When you define an IP address range, you can also specify a number of the port, and see if a device in your network is using a specific service (defined by the port). Angry IP Scanner also lets you save all the scan results into multiple formats, such as TXT, XML, CVS, etc.
When you scan, youll know what hosts are alive, their response time, hostname, MAC address, etc. If you want even more information, you can extend results by developing Java plugins.
Price:
Open Source and 100 free.
Download:
Get Angry IP from its official site. 2. SolarWinds Ping Sweep
Ping Sweep from SolarWinds helps you find free IPs and identify which ones are unavailable. It is classified as a networking discovery tool from the SolarWinds Engineers Toolset. A comprehensive network software, that includes over 60 handy tools. Ping Sweep from SolarWinds is included in the Engineers Toolset and is dedicated for ping testing. For the MAC address, port scans, SNMP scans, etc, there are more dedicated tools in the Engineers Toolset.
Just as when you ping from the command line, this tool shows the DNS name for each IP and response time. It can also let you export results in different formats such as CSV, TXT, XLS, and to an HTML page.
Price:
SolarWinds Engineers Toolset starts at $1,380.00 and includes over 60 must-have tools.
Download:
Get a fully functional Engineers Toolset for 14 days by registering to SolarWinds official site.
IP Address Tracker Tools
Having a map of IP addresses, MAC addresses, used ports, etc, is great for networking inventorying and may help with some troubleshooting cases. But a list can not control and display real-time results.
An IP address Tracker is a good upgrade to our set of tools and commands described so far. It does allow scanning multiple subnets and displaying results, but it also allows you to keep track of one or more IP addresses. Scan For Ip Addresses On Network Cmd
An IP Address Tracker will notice when an IP address is released. This can be either because the device lost connectivity or it changed IP address. It will help you minimize IP addressing conflicts (when two devices are trying to take the same IP) and reduce DNS errors. 3. MyLAN Viewer
MyLAN Viewer is a NetBIOS and IP address scanner for Windows systems. Just like the IP Scanners shown above, this tool will scan a network and show devices in an easy-to-read format.
But MyLANViewer goes beyond, and not only shows computer name, IP, and MAC, but also NIC, OS version, logged users, shared folders, and much more.
This tool is able to track specific IP addresses and show notifications when their state change. With it, you can also keep track of network security by showing port information and detecting rogue DHCP servers. MyLAN Viewer tracks all devices in the subnet including hidden, and displays alerts when new devices enter the network, and others go.
This tool can also display the following metrics as well:
Display Whois data.
Perform traceroute.
Manage Remote Shutdown and Wake On LAN (WOL).
Monitor wireless networks.
Price:
Free, but only available for Windows systems.
Download:
Get MyLAN Viewer from its official site. 4. SolarWinds IP Tracker
SolarWinds IP Tracker is a standalone software and completely free. In addition to creating inventories of all devices, this tool allows you to scan, track, and manage IP address, including their event logs, all in a single place. SolarWinds IP Tracker is the free version and feature-limited of the much coveted IP Address Manager.
But the IP Tracker does an amazing job to provide a centralized view of the entire IP addressing scheme. It lets you monitor 256 (one subnet) IP addresses for free. Additionally, this tool allows basic management functionalities with tools such as, Ping, Telnet, Traceroute. The best of all is that, with SolarWinds IP Tracker you can detect IP address conflicts created by misconfigured DHCP servers.
SolarWinds IP Tracker is only supported by Windows systems.
Price:
100 Free.
Download:
Register in SolarWinds to download the software for free.
IP Address Management (IPAM)
Basic IP Address Scanning should be enough to manage small networks. But when networks scale they depend on multiple subnets and detailed management requirements. Although SolarWinds IP Tracker is able to find IP address conflicts, it is not able to control them.
Sometimes large-scale networks have standalone DHCP and DNS Servers in order to assign addresses to multiple subnets. But IP conflicts occur and it is really challenging to manage them manually. An IP Address Management or IPAM is a piece of software able to actively control DHCP and DNS. It also gives you the ability to manage multiple subnets. 5. SolarWinds IP Address Scanner
Among SolarWinds powerful tools, the IP Address Manager does everything a large-scale enterprise needs to manage its addresses properly. It automates many processes to make IP Address management easier. From automated IP address tracking, quick static IP reservations, to multi-vendor DHCP and DNS support.
SolarWinds IPAM comes with an integrated IP address management, DHCP, and DNS tools to administer your entire network.
One of the most commonly used tools from this bundle is the IP Address Scanner. This tool allows you to create automated IP address scans to maintain an updated inventory of all IP address blocks in the network. This is achieved by sending regular ICMP and SNMP polls. The automatic scans use ICMP polls to gather status of the IP address and hostname information. It also uses SNMP to find information on MAC addresses and other vendor information. SolarWinds IP Address Scanner supports both IPv4 and IPv6 address management. Angry Ip Scanner Mac Address
SolarWinds IPAM also provides detailed reports of your IP address in real-time.
Price:
Download the Free Trial for 30 Days!
Download: Scan My Network For Ip Addresses Mac Os
Get a fully functional SolarWinds IPAM for 30 days by registering to SolarWinds official site.
