Sometimes you may get a “connection refused” message for mail, the web, or other services. Test whether a port is open eliminates the application from the equation. Steps as below: –
Steps To Check Server Open Port
1. Find out what server and port you need to test: web is usually 80, outgoing mail is 25, and POP is 110, as examples.
2, Go to the Start Menu -> “Run…”
3. Type “telnet server-name PORTNUMBER”.
4. If the window hangs while saying “Connecting …” and then goes away, the port is not accessible.
If the window instantly goes away, the port may not be accessible.
If the window display some kind of text, like “220 ESMTP …” then the port is open.
5. If there are problems, try again using the IP address instead of using the server hostname
Next» Server Port Scanning