A port scanner is a software program which scans a server for open ports. Port scanners are usually used by network administrators to monitor network ports on a system, server or IT environment and thus examine the network security.
Based on the scan requirements, a port scanner can have multiple operation modes like Vanilla (scans all the ports on a system or server), Strobe (selected ports are scanned), UDP (scans for open UDP ports), Sweep (a similar port number is probed on more than one device), etc.
However, hackers use port scanners to figure out open ports for exploiting and running malicious codes on a host computer or server. One excellent idea to keep your network safe is to close the unused ports.
For this, you can use some of the free port scanner software available to identify open ports and take the corresponding action. In this article, you will get to know about some of the most popular free port scanner software suitable for your purpose.
What are the popular free port scanner softwares?
Some of the port scanner software programs can be downloaded and installed whereas some of them can be accessed from any OS via a browser because they are online services.
The list of the popular free port scanner software is as follows.
This software tool is available for Windows users only. Solarwinds is a free utility and one of the leaders in the network software industry.
It is suitable for any business of any size and can be run through either a graphic interface or the command line.
Using Solarwinds Free port scanner, you can scan all the devices on your network, or you can also opt to scan only a section of the network. You can even scan a single device.
There is a default value provided for the port numbers in the search settings which limits the scan to well-known ports only.
However, you can also enter any range of port numbers of your choice.
Using Advanced settings, you can check TCP or UDP activity or both of them. You may also add a Ping check and DNS resolution to a search.
Results show a very long list of all possible IP addresses within the scope. You can shorten the list by specifying to show results for active hosts only.
The abbreviated list includes details about opened, closed and filtered ports of every active device.
Nmap or Network Mapper is a free network testing tool. It is used for network exploration and security auditing by system administrators, and network engineers.
It is compatible for Windows, Linux, BSD Unix, and Mac OS.
Nmap can be run using command line terminal or GUI interface. Nmap offers a range of features as mentioned below
Active port scanning
This utility scans all the ports on all the computers connected to your network or router. The follow-up tests are conducted on the open ports only, as discovered by Nmap.
Using Nmap, you can find out the hosts responding to the network requests.
Nmap can identify the operating system name and version as well as the network details where the host is running.
Application version detection
Nmap can also detect the types of apps running and their version numbers.
You can perform the basic system check by a standard test using ping. For the ping-less method, you can go for a complete scan, scan all TCP or all UDP ports.
There is a provision of intense scan using SYN stealth methodology, but it is very time-consuming.
Zenmap is the official NMAP frontend interface (GUI) and is very user-friendly. It functions for a single router or computer. You can perform scans on remote hosts effortlessly using Zenmap.
Zenmap saves scan results in a database as well as lets you search them, compares current results with previous ones and has many other characteristics.
Angry IP Scanner has a multithreading approach separating every scan. Therefore, it has a very fast scanning speed. It is free and suitable for Windows, Linux, and MacOS.
First, the Angry IP scanner pings every IP address to check if they are live and then it resolves the hostnames, scan ports, etc. Using Angry IP scanner, you can quickly scan for open ports on any remote network.
You can directly download and run this utility, without any installation. It additionally contains NetBIOS information consisting of the computer name, workgroup name, currently logged in user and MAC address.
It offers easy plugin integration with Java language and can save results in CSV, TXT, HTML, XML or IP-Port list files.
From the Port Scanner page on the Port Checkers website, you can conduct an online test of ports on your computer.
A long scan will check 36 of the well-known ports, and a quick scan will check just 13 of these ports.
It will determine whether these ports are accessible from the internet and whether a service is running on each of them.
The checks by the port scanner include FTP data and control channel (ports 20, 21), TFTP and SFTP ports.
Also, networking protocol ports of DHCP, SNMP, and DNS are checked. Besides these, some communication and security services like HTTP, HTTPS, SMTP, SSL, Telnet, etc are also tested.
Sometimes, it may be necessary to keep some of these ports opened. The scan results are displayed in a table on the web page. The service offered is free.
TCPView is a free utility, available for Windows systems. It also includes a tool TCPVcon, its command line version with same features. TCPView is very convenient and informative in its way of approach.
The way it works is different from many of the commonly used port scanner software tools.
Instead of searching the ports and then checking for an active service running on each of them, TCPView first checks all the processes running on a computer.
It then determines the ones linked to the ports and subsequently lists the port numbers. This approach offers much more details than any external scan.
TCPView covers both TCP and UDP ports. The result shows the number of packets, number of bytes of sent data and received data on each port. This display is refreshed each second.
This is a handy site for port checking and port scanning. It is a free online tool where you can enter an IP address and a range of ports for verification.
You can make any number of port entries, and by this, you can eventually check all the ports on your computer.
However, the site alerts you that a port number range exceeding 500 will consume a lot of time and an extensive range may initiate a never-ending search. It is wise to complete your full scan in segments.
In the Normal Scan, it checks which ports are visible externally and which are covered by firewalls. In the Advanced port scan option, you can launch a connect() command test or an SYN stealth test.
Some other famous port scanners
Though no latest support or upgradation is available for LANSpy, you can still download its last version which released on April 30, 2005.
It is a collection of network utilities bundled into a single program with a user-friendly interface.
It assists the network administrators by showing the processes on remote devices, displaying the installed applications on workstations, detecting shares, open ports, and user accounts, etc.
LANSpy also collects various types of information like Ping, Domain Names, NetBIOS names, MAC address, server details, Time, disks, security options, shared resources, etc.
Open Port Scanner can be found on the Web Tool Hub website. It is a free tool and allows you to select the ports to be scanned.
You can enter the numbers individually or in ranges. However, at a time, only ten ports can be checked. The results are quickly displayed in tabular form with the status of each port and the corresponding service.
You can export the result into a CSV file.
Free Port Scanner 3.5 is available from Major Geeks and runs on Windows systems. You can scan ranges of port numbers using this utility and at one go if you have ample time.
The interface determines the IP address of your device while launching and by default, provides a list of ports for scanning. For a wide range, the process may be slow.
You can also scan the ports on your wifi router using Free Port Scanner 3.5.
Netcat is available for Windows, Linux, and MacOS. It exists since 1995, and the last official version was launched in 2004.
It has inbuilt port-scanning characteristics and is used for TCP and UDP port scans, and verbose port scanning.
Netcat can also perform other activities like open remote connections, tunneling and proxying, run remote commands, etc.
So, you are now aware of different free port scanner softwares available in the cyber world. You know that port scanners aid in identifying open ports available on a network host. Network administrators and security officials utilize it to figure out existing vulnerabilities in their systems.
However, cybercrooks use it to intrude and attack different systems and usually exploit these weaknesses. So, using a port scanner, one can quickly detect the open ports. It is advisable to keep unused ports closed.
There are several port scanner software is available on the internet. For example, Solarwinds, Nmap, IP Fingerprints, TCPView, etc. are great utilities used worldwide for this purpose.