Find and Close Open Ports

Identifying and closing open ports is one way to minimize network vulnerabilities.  You can use Fing to find open ports and close them if you want to improve security.

What are ports?

Ports allow computers/devices to run multiple servers/applications.

An open port is an active port that can receive data. A closed port is one that is not receiving or rejects data.  You may wish to close these ports if you do not use them. Different ports and their numbers are used for different purposes. For example, ports 3000 and 3030 are used by software developers while port 80 is used by web access. Think of ports as open windows in a locked house and the router as the main door.

A port number uses 16 bits, so it can have a value of 0 to 65535 decimal. 

Open ports can impact the confidentiality, integrity, availability, and security of your organization/setup:

• Confidentiality: Open ports and the programs listening and responding to them, can reveal information about the system or network architecture. Open ports can leak banners, software versions, content, the existence of the system itself, and what type of system it is.
• Integrity: Without open port controls, software can open any candidate port and immediately communicate unhindered. This is often relied upon for legitimate programs, as well as different types of malware.
• Availability: Your network and the services running on open ports still process incoming traffic, even if the requests are invalid. This can result in denial of service (DoS) attacks.
• Security Risk:  Unwanted access can find its way through existing routing devices. Any application on a device may request that the router opens a port on its behalf to contact an entity outside of your local network.

Find Open Ports

When an application uses a service, it uses some ports. Once the application has used the ports, the ports become free. Once a port is free/not in use, the Fing App will tell you the port is open and no application is using it, thus advising you to close the port.

Find Open Ports Using Fing Desktop

• Click the Tools tab in the left sidebar
• Click Find Open Ports. This will take you to the Port Scan page, where you can either enter a website or select the device on your network from the dropdown list. You can also change the ports scanned by the app. If you want to scan for all 65k ports or just the common ports.

Find Open Ports on the Fing Mobile App

• Open Fing Mobile.
• Click the Tools tab in the bottom toolbar.
• Click Find open ports under the heading Improve your network security. This will open the Find open ports page, where you can either enter a website or select the device on your network from the dropdown list.
• Click the blue Find open ports button.

The most common ports are:

• FTP (21)
• SSH (22)
• Telnet (23)
• SMTP (25)
• WHOIS (43)
• DNS (53)
• DHCP (67, 68)
• TFTP (69)
• HTTP (80)
• POP3 (110)
• SFTP (115)
• IMAP (143)
• SNMP (161)
• HTTPS (443)
• LPD (515)
• rsync (873)
• IMAP SSL (993)
• POP3 SSL (955)
• SOCKS (1080)
• Proxy (3128)
• MySQL (3306)
• RDP (3389)
• PostgreSQL (5432)
• VNC (5900)
• TeamViewer (5938)
• HTTP (8080)

Test router vulnerabilities tool

On Fing Premium and Fing Starter, the Test router vulnerabilities tool on Fing Desktop prevents risks to your network and unauthorised open ports. To do this:

• Click the Tools tab in the sidebar
• Click Test router vulnerabilities

Click here for more information on open ports and device vulnerabilities.

Close Open Ports

You can close open ports only using Fingbox or Fing Agent with Fing Mobile App.  After you show open ports, you have the option to close.

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