How to See the Ports That Are Blocked on a Router (2024)

FAQs

How to See the Ports That Are Blocked on a Router? ›

We recommend using a reliable port forward tool like www.portchecktool.com. The port forward checker tool is a valuable resource for network troubleshooting. It helps you check whether your ISP (Internet Service Provider) is blocking specific ports, such as the commonly restricted HTTP port 80 and SMTP port 25.

Enter "telnet + IP address or hostname + port number" (e.g., telnet www.example.com 1723 or telnet 10.17.xxx.xxx 5000) to run the telnet command in Command Prompt and test the TCP port status. If the port is open, only a cursor will show. If the port is closed, a message will say Connect failed.

By default, no ports are forwarded in a router - they're all blocked. To “open” (forward) a port, set the computer listening on that port to a static IP. (See if the router has that ability - look for something like DHCP reservations.) Then, in Security, forward that port to that IP address.

The port checker is a tool you can use to check your external IP address and detect open and closed ports on your connection. This tool is useful for finding out if your port forwarding is setup correctly or if your server applications are being blocked by a firewall.

Type nc -vz (your router's IP address) (port) .

For example, if you wanted to see if port 25 is open on your router, and your router's IP address is 10.0. 0.1, you would type nc -vz 10.0. 0.1 25 .

If you would like to test ports on your computer, use the Windows command prompt and the CMD command netstat -ano. Windows will show you all currently existing network connections via open ports or open, listening ports that are currently not establishing a connection.

1 Identify the blocked ports

You can use various tools and methods to do this, such as ping and traceroute, telnet, and port scanners. For example, you can use the ping command to test the connectivity and latency between your device and a destination IP address or domain name.

Use Windows Search to search for cmd. Right-click the first result and then select Run as administrator. Type netsh firewall show state and press Enter. Then, you can see all the blocked and active ports in your Firewall.

How do I tell if my router is blocking a website? ›

You can use a website like isup.me, down.com, or isitdownorjust.me. If it tells you that the website is down for everyone, it has nothing to do with your ISP. However, if it's unavailable just for you, your Internet provider is involved.

Type "netstat -a" at the command prompt and press "Enter." After a few seconds, all of the open ports on the computer. Locate all of the entries that have an "ESTABLISHED," "CLOSE WAIT" or "TIME WAIT" value under the "State" header. These ports are also open on the router.

To test if a given outgoing port is blocked on your network by some malicious middlebox, you can try to telnet into a server that has a service running on that port. In this example, we use portquiz.net--which is a public service designed for this purpose. It uses iptables' nat table and has all tcp ports open.

We recommend using a reliable port forward tool like www.portchecktool.com. The port forward checker tool is a valuable resource for network troubleshooting. It helps you check whether your ISP (Internet Service Provider) is blocking specific ports, such as the commonly restricted HTTP port 80 and SMTP port 25.