Top 10 Open Port Scanner and Port Checker Tools for 2020

Port scanner and port checker tools are one of the most essential parts to find the open ports and status of the port.

The open ports mean a TCP or UDP port number that is arranged to acknowledge packets.

Web pages or FTP services require their particular ports to be “open” on the server so as to be freely reachable.

What is the Open Port Scanner?

An open port scanner is a tool which is used to check the external IP address and identify open ports on the connection.

It is used to detect whether the port forwarding is setup accurately or the server applications are being blocked by a firewall.

Port Checker tools used to examine the network for ports that are commonly forwarded.

Few ports, such as port 25, are usually blocked at the ISP level trying to intercept suspicious task.

Each data contains a port number, which allows the protocols to determine their desired location and redirect them accordingly.

Is Port Scanning illegal?

Port scanning itself not illegal, but scanning the destination host without authorization is illegal and you will get into trouble.

TCP Port scanners help the server administrators and penetration testers to examine at which ports the data is entering into the network and to protect from invaders.

Most Used Ports

20 FTP – Data
21 FTP – Control
22 SSH Remote Login Protocol
23 Telnet
25 Simple Mail Transfer Protocol (SMTP)
110 POP3
115 Simple File Transfer Protocol (SFTP)
118 SQL Services
53 Domain Name System (DNS)
143 IMAP
389 LDAP
37 Time Protocol
123 Network Time Protocol
530 Remote procedure call
547 DHCPv6 server

How to Scan Open Ports in Windows?

Scanning can be done using the command prompt.

  1. Press Windows key and run key at the same time to open the command prompt.
  2. Type cmd and hit enter.
  3. In the command prompt type “netstat -a” and hit enter.
  4. In a few seconds, it displays a complete list of ports that establish the connection.
Scan Open Ports in Windows
How to Scan Open Ports in Windows

Security Risk due to Open Ports:

Most of the suspicious software’s behaves like service waiting for connections from a remote assailant so as to give him data or authority over the machine.

The most common security practice is to close unused ports in private machines, in order to block known access to any service which may keep running on the PC without the client’s information, regardless of authorized service being misconfigured or because of the suspicious software.

Best Port Checker & Port Scanner Tools

  • Advanced Port Scanner
  • TCP Port Scan with Nmap
  • Network Port Scanner Tool
  • DNS Tools
  • Web Proxy and Privacy Tool
  • Solar winds Port Scanner
  • IP Tool
  • UltraTools
  • Yougetsignal

Advanced Port Scanner

Open Port Scanner
Output displaying ports enabled

This Open port scanner is the fastest, easy to access and freely available everywhere.

It helps to find out the open ports on network computers and extract a kind of programs that are running on detected ports.

These programs have an adaptable interface and usable functionality.

TCP Port Scan with Nmap:

This Open Port Scanner tool helps to identify which TCP port is open on your target machine and also provide OS information, service information and also traceroute. T

Nmap Port scanner tool is a web interface for the widely known Nmap port scanner which is implemented with the correct parameter so as to give speed and accuracy.

Open Port Scanner
Zenmap/Nmap port scanner

The scanning process is sending packets to each port and listening for acknowledgment.

This is called ‘SYN scan’, which sends TCP SYN packets to each port. If a port replies with SYN-ACK, it is flagged as open and an RST is sent back by Nmap port scanner.

In this way, no full TCP connection established with the target machine.


IPVOID helps to identify services that are running on the server, view TCP open ports.

It also checks and verifies whether the firewall is working accurately. There are security services which block IPs that you don’t hold, so try not to check.

Open Port Scanner
IPVOID port Scanner

Network Port Scanner Tool

This Open port scanner tool helps to check services which are available and running on the server.

If we want to check what OS version is running, ports are open on a server and server has enabled firewall or not, then, in this case, to check all above information, it uses raw IP packets.

DNS Tools

It helps you to identify which service is accessible outside of the intranet. Machines use a router with NAT to bind with the internet can’t be obtained outside of the intranet.

Although, by using port forwarding, ports can deviate from the router to the particular machine.

This Open port scanner online allows to verify redirection works correctly or not.

Web Proxy and Privacy Tool

This Open port scanner online tool is also known as  “ . If anyone wants to hide their identity and access anything and everything, go for Web proxy.

This tool hides and changes your IP address, location and you will stay incognito while using the browser.

Open Port Scanner
Proxy Tool

It is a median to the machine and required website. You can also watch blocked content and play online games as well.

You can surf the internet with maximum speed and connection. It gives protection, privacy, and liberty on any device while browsing.

Solar winds Port Scanner

It scan’s all the IP addresses and TCP and UDP ports to check network vulnerabilities.

You can run the scan from the command line as well, save scan configurations also, minimize run time scan with multi-threading. Trace end-user and terminal machine connection activity.

It recognizes unknown vulnerabilities and network protocols.

Solar Winds Port Scanner

IP Tool

IP tool is known as “ “ Port scanner.

This tool scans the network for open ports and decided if those open ports need to be closed to allow network security and fewer vulnerability.

This Open port scanner tool shows which ports are open for communication on a network. If in case, a port is opened, it is for remote communication.


With Ultra tools you can check the DNS performance and the DNS records specified to the domain or the hostname.

DNS Traversal Tool gives you more information on whether the DNS servers have propagated to all Nameservers.


Yougetsignal is the open port checker tools that let you check any external IP address for open ports.

It is a useful tool to check for the restriction placed in the Firewall. With this tool, you can check for all TCP and UDP ports.

Open Port Scanner and Port Checker Tools
Yougetsignal Open port checker

With the listed above port scanner tools, you can determine the open ports in the network infrastructure.

It is always recommended to close the ports if they are not in use for security reasons.


Listed are some of the free tools available online to check for the open ports on the server and for other DNS queries.

We have categorized some of the best port scanner and port checker tools to help to find the open ports and other port-related operation while performing a penetration test on the network.


  1. A helpful martial, it really shows your dedication and your hard work. I really appreciated your content, helps me a lot in different matters…

  2. Hi Tanya Bhateja,
    Thanks for providing the great info with great content. Hoping to see more valuable content from your end.

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