This port check and firewall test allows you to perform a limited port scan against your public facing IP address. Easily determine which ports are open, and whether your firewall is working correctly. For a more in-depth port scan tool try the Online Port Scanner where you can scan any IP address and test all 65535 TCP ports.
What is a port check?
A port check will test an IP Address for open ports. This is otherwise known as a port scan. Try our other online port scanner that is able to scan any IP Address. The tool on this page however is a quick port check that will test your current IP Address or perhaps a proxy if you are coming via proxy for some common services.
Port Check Details
The scanned ports are 21 (ftp), 22 (ssh), 25 (smtp), 80 (http), 443 (https) and 445 (windows sharing).
This tool allows you to check your Internet facing IP address for open ports and discover if your firewall is in place and working. To scan other IP addresses a more advanced port scanner with the ability to check open ports on any IP address is available on the nmap port scanner page.
How to Find Open Ports
In order to find open ports this system will send a TCP 3 way handshake to your IP Address on each of the 8 ports. Depending on how the system responds a determination is made as to whether the port is open, closed or filtered.
Test Firewall through Port Status
Following results from the port check it is usually possible to determine whether a Firewall is present and blocking all traffic to ports that are not available. If some ports are in a closed state and some filtered this indicates a firewall or router may be blocking traffic but is not necessarily configured correctly as closed ports in most cases should be filtered by the firewall.
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