I'm using Saudi Arabia proxy server 18.104.22.168:443 I can't the pop3 mail with default port 25 & 110, pop3s 995 & 465 I still wanna know how can i check which port is block by proxy server.
First of all, are you sure that you need to connect to your mail servers through the proxy? A http proxy is typically only meant for web connections.
If you do, you need to make sure that your email applications are actually establishing their connections through the proxy. By default, most email applications will not connect via a http proxy server. You can do this by monitoring your network connections using whatever tools are present on your OS. At the minimum, you should have
Secondly, if your email applications are really using the connection through the http proxy, it is possible that the proxy server has been configured to only allow connections to port 80 and 443. You can test this by telnet into the proxy (possibly over SSL) and issuing a