Check if a TCP port is open
Test a connection to any host and port from every check server
What the TCP port check shows
Every check server tries to open a TCP connection to the host and port you entered.
Connection result
Connected, refused, timed out or unreachable: the exact outcome of the TCP handshake from each location.
Connect time
How long the handshake took, a clean measure of network latency to the service.
Any TCP service
Web and mail servers, databases, SSH, game servers — anything that listens on a TCP port.
Frequently asked questions
Short answers about how the check works and how to read its results.
How do I enter the port?
Add it after a colon: example.com:443 or 1.1.1.1:53. Put IPv6 addresses in brackets, like [2606:4700:4700::1111]:443. Without a port, port 80 is checked.
What is the difference between refused and timed out?
Refused means the host answered, but nothing listens on the port. Timed out means there was no answer within 3 seconds, which usually means a firewall silently drops the connection.
Does the check send any data?
No. It only opens a TCP connection and closes it right away.
Can I check a UDP port?
No, only TCP. UDP has no handshake, so an open UDP port cannot be confirmed without speaking the protocol of the service.
All tools in one place
Check availability, latency and routing of websites, servers and IP addresses from different locations.