If you need to know what’s currently connected to your network, your best bet is to scan it and see what actually responds. While this can be done manually, on all but the smallest of networks, this can quickly turn into a considerable—and time-consuming—endeavour. Fortunately just as there are a million reasons why you’d need to scan your network, there are also a million products that can help you do just that. So many options are available that picking the best tool for the purpose can be an overwhelming challenge. Today, we’re having a look at some of the best network scanner tools.
We’ll begin our discussion by having a look at network scanning. We’ll try to cover the how and the why of it. Next, we’ll be introducing ping. After all, this is by far the most useful tool for network scanning and many integrated network scanning tools use it in the background or they use similar techniques. Knowing ping’s inner workings will help you better understand how network scanners operate. And last but not least, we’ll review some of the very best network scanning tools.
Network Scanning 101
Other than the pure fun and enlightenment of knowing what IP addresses are in use, there are several reasons one would want to scan IP addresses. First and foremost is security. Scanning IP addresses on a network allows you to quickly discover unauthorized devices. These could, for instance, be devices connected by malicious users to spy on your organization.
But even well-intentioned users can sometimes wreak havoc by connecting their personal devices. I recall that user who prevented many of his colleagues from accessing the corporate network when he connected his home Internet router to it. He just needed a couple of extra ports to connect an additional test computer and thought he could use the switch built into his router. Unbeknownst to him, the router started issuing IP addresses from its built-in DHCP server. And several of his colleagues got assigned erroneous IP addresses.
Other than for security reasons, scanning IP addresses is also the first step in any attempt at IP address management. While many—if not all—IP address management (IPAM) tools do include some form of IP address scanning, many choose to manage IP address using a manual process instead of an integrated tool. In these situations, IP address scanning tools become a necessity.
For people without any kind of formal IP address management process, scanning IP addresses is possibly even more important. It will often be the only way to ensure that there are no IP address conflicts. It can, in fact, be considered a rather crude way of pseudo-managing IP addresses.
No matter what you need for scanning IP addresses is, most tools are based on Ping. Let’s have a look at this ubiquitous albeit antique utility. Ping was created out of necessity back in 1983 proving once more that necessity is the mother of invention. Its developer needed a tool to help in debugging an abnormal network behaviour he was observing. Its name refers to the sound of sonar echoes as heard in submarines. Today, ping is present on almost every operating system, yet its implementation varies somewhat between platforms. Some versions are offering multiple command-line options which can include parameters such as the size of each request’s payload, the total test count, the network hops limit, or the interval between requests. Some systems have a companion Ping6 utility that serves the exact same purpose but uses IPv6 addresses.
Here’s a typical use of the ping command on Linux (the “-c 5” option below tells ping to stop after five repetitions, mimicking the Windows default behaviour):
$ ping -c 5 www.example.com PING www.example.com (184.108.40.206): 56 data bytes 64 bytes from 220.127.116.11: icmp_seq=0 ttl=56 time=11.632 ms 64 bytes from 18.104.22.168: icmp_seq=1 ttl=56 time=11.726 ms 64 bytes from 22.214.171.124: icmp_seq=2 ttl=56 time=10.683 ms 64 bytes from 126.96.36.199: icmp_seq=3 ttl=56 time=9.674 ms 64 bytes from 188.8.131.52: icmp_seq=4 ttl=56 time=11.127 ms --- www.example.com ping statistics --- 5 packets transmitted, 5 packets received, 0.0% packet loss round-trip min/avg/max/stddev = 9.674/10.968/11.726/0.748 ms
Ping’s Inner Workings
Ping is a pretty simple utility. All it does is sending ICMP echo request packets to the target and waiting for it to send back an ICMP echo reply packet. This process is repeated a certain number of times—five by default under windows and until it is manually stopped by default under most Unix/Linux implementations. Once the command terminates, response statistics are compiled and displayed. The utility calculates the average delay between the requests and their respective replies and displays it in its results. On most *nix variants, it will also display the value of the replies’ TTL (time to live) field, giving an indication of the number of hops between source and destination.
For the command to work, the pinged host must abide by RFC 1122. The standard specifies that any host must process ICMP echo requests and issue echo replies in return. And while most hosts do reply, some disable that functionality for security reasons. Firewalls also often block ICMP traffic. To circumvent this, the better IP address scanning tools can use a type of packet different from ICMP to check if an IP address is responding. Pinging a host which does not respond to ICMP echo requests will provide no feedback, which is exactly like pinging a non-existent IP address.
The Best Network Scanner Tools
This list includes some of the best tools we could find for network scanning. We’ve incorporated tools for most platforms so that whether you’re a Windows, Linux or Mac user, there’s something in there for you, Some of the tools on our list are pure network scanners while others are broader tools that do include a scanning module.
1. SolarWinds IP Address Tracker (FREE DOWNLOAD)
First on our list is a great tool from SolarWinds, a company that is well-known in the network administration field for making some of the best tools and also for publishing many free tools, each addressing a specific need of network administrators. Together with free tools such as the Advanced Subnet Calculator or the Kiwi Syslog Server, the SolarWinds IP Address Tracker is one such free tool.
- FREE DOWNLOAD: SolarWinds IP Address Tracker
- Official Download Link: https://www.solarwinds.com/free-tools/ip-address-tracker/registration
The SolarWinds IP Address Tracker can be used to manage and track up to 254 IP addresses. This limitation makes it a fine tools for smaller installations. It will track IP address availability and alert you of an upcoming shortage of available IP addresses. It will also automatically detect IP address conflicts and alert you when it finds one. This feature-limited tool won’t interact with your DNS and DHCP servers, though. You’ll have to manually fix any issues it finds. It’s got an attractive dashboard-based user interface with colour-coded status and it also features historical trends and events reports.
2. SolarWinds IP Address Manager (FREE TRIAL)
For a more complete, enterprise-grade tool, the SolarWinds IP Address Manager might be just what you need. It starts where the IP Address Tracker stops. This is a full-featured IP address management tool that has none of the limitations of the free tool. This one can manage up to 2 million IP addresses, enough for the biggest environments.
- FREE TRIAL: SolarWinds IP Address Manager
- Official Download Link: https://www.solarwinds.com/ip-address-manager/registration
Although it doesn’t include DHCP or DNS capabilities, the IP Address Manager will interact with your existing DNS and DHCP servers, making it a true DDI solution. Of course, the tool features automatic IP address tracking. It wouldn’t be in this list if it didn’t. It will automatically monitor your subnets so that you always know how IP addresses are used. The system will alert you of IP address conflicts, depleted scopes, and mismatched DNS records.
The tool integrates with DHCP servers from Microsoft, Cisco, and ISC and will work with BIND and Microsoft DNS servers. Pricing starts at $1 995 and varies according to the number of managed addresses. A free 30-day trial is available if you want to test the product before purchasing it.
3. Angry IP Scanner
The Angry IP Scanner is a multi-platform tool that will run on Windows, Mac OS, and Linux. This tool can scan complete networks or subnets but also an IP addresses range or a list of IP addresses in a text file. It uses Ping to find IP addresses that are responding but it will also resolve hostnames and MAC address vendors as well as provide NetBIOS information for hosts that support it. This tool is also a port scanner and can list the open ports on each responding host.
The Angry IP scanner is a GUI-based tool but there’s also a command-line version that you can use. This is useful for including the tool’s functionality in your scripts. Results are displayed on the screen in a table form and can be exported to several file formats such as CSV or XML.
4. Advanced IP Scanner
The Advanced IP Scanner has an interesting twist. The tool runs on Windows and is made for Windows. More about all that in a moment. This software simply takes an IP address range as its input. You could also supply the tool with a text file containing a list of IP addresses. The tool will scan the addresses and provide you with a list of those addresses that respond. But you don’t only have IP addresses, the tool will also display each host’s name, MAC address and network interface vendor.
For Windows hosts that the tool discovers, you get much more functionality. For instance, the tool will list network shares. And clicking any share opens it on your computer. You can also start a remote control session using either RDP or Radmin or remotely turn a Windows computer on–provided it has wake on LAN–or off.
5. SoftPerfect Network Scanner
The SoftPerfect Network Scanner will scan a range of IP addresses and list those that respond along with their MAC address, hostname and response time. It can also be used as a port scanner and will optionally list what IP ports are open on each host.
Just like our previous entry, additional functionality is available for Windows hosts. This tool will, for instance, display all shares on each host. Even hidden shares will be displayed. It can also list what user account(s) are currently connected to each Windows computer. Furthermore, the tool will let you remotely access computers and run commands remotely. And finally, you can broadcast messages to the discovered computers.
6. LizardSystems Network Scanner
The main difference with the LizardSystems Network Scanner is that it is browser-based. It runs only on Windows and requires Internet Explorer. As for its features, they leave nothing to be desired. The tool is easy to use, it offers great performance thanks to its use of multi-threading, and it’s scalable. There’s actually no limit to the number of addresses you can scan.
There are also quite a few advanced features such as results filtering or customizable status checks that will check for any port you specify. It will also retrieve NetBIOS information as well as verify access rights to remote resources. And if you want to manipulate the results, you can export them to HTML, XML, or text.
LanScan from Iwaxx is available from the Apple app store. It’s a simple application that does just what its name implies: scan a LAN. It is a free, simple and efficient IPv4-only network scanner. It can discover all active devices on any subnet. It could be the local one or any other subnet that you specify. In fact, it is quite flexible when it comes to specifying what to scan and it can be as small as a single IP address and as large as a whole network. A unique characteristic of this product is how it will use ARP to scan a local subnet and use ping, SMB, and mDNS packets to scan external and public networks.
This product has several advanced features. It will, for instance, automatically detect configured interfaces. It will also display the IP address, MAC address, hostname and interface card vendor associated with each discovered IP address. It will also discover SMB domains if they are in use and will do hostname resolution using either DNS, mDNS for Apple devices or SMB for Windows devices.
In-app purchase will let you upgrade the app to the pro version which has only one extra feature: it will display the full hostname of each discovered host. The free version will only display four full hostnames and the first 3 characters of the remaining ones.
8. IP Scanner For Macintosh
The IP Scanner for Macintosh will scan your LAN to identify what IP addresses are in use and identify all computer and other devices on the network. The product is free for use on small home networks of up to six devices and paid Home and Pro versions are available for larger networks. The tool yields powerful results yet it is easy and intuitive to use. Local networks are scanned automatically and custom IP address ranges can be added and scanned manually
The IP Scanner for Macintosh is designed to allow you to customize your scan results. Once a device has been identified, you may assign it a custom icon and name to more easily recognize it at a glance. The tool will let you sort the results list by device name, IP address, MAC address or Last Seen timestamp. It can also give you an overview of the current network or show you changes over time.
The results display is highly customizable and you can adjust columns, text size, bezel transparency, and more. Double-clicking a device gives you more information and allows you to customize its appearance. Right-clicking a device will let you initiate a ping sequence or run a port scan of it.
9. Bopup Scanner
It is unexpected to see a product from B-Labs on this list as the company usually specializes in messaging systems. In fact, its Bopup Scanner is its only network administration tool. It is a free tool for the Windows operating system.
This tools will scan your network and output a list of all connected devices. It displays IP addresses, hostnames, and MAC addresses. It will also tell you if a web server is responding on each host it tests. You can drill down on each host to view more information such as a list of available shares. Option-wise, the tool will let you specify exactly what IP addresses to scan and you can also set the response timeout to prevent unresponsive IP addresses from slowing down the process.
10. MyLanViewer Network/IP Scanner
The MyLanViewer Network/IP Scanner is a free IP address scanner for Windows whose main differentiating factor is how results are displayed. Instead of a table with a list of IP addresses and corresponding parameters, this tool presents the results in a hierarchical way. It looks like the left pane of a Windows Explorer window.
This tool will scan the whole network where the computer used to run it is connected. It will show each responding host as a node on a tree structure. Clicking the plus sign next to any entry will reveal more information about it. It displays the same complement of data as most other tools.