Are Mail Server Ports Reachable?


Error: Javascript is disabled.

SMTP(outbound) 25(smtp) 465(smtps) 587(submission)
POP3(inbound) 110(pop3) 995(pop3s)
IMAP(inbound) 143(imap) 993(imaps)
Control Ports 11111(closed) 80(http,open)

What's this all about?

This site is a portscanner, which is scanning the standard mail server ports in order to determine if there's some kind of firewall between your computer and public mailservers in the internet, which blocks the use of mail services.

System Requirements

Operating System Windows. JavaScript has to be enabled and you should use a compatible web browser, and you should open the required ports in your webbrowser for firefox and chrome(See below). It may help to get a more assured result if you reload the site a couple of times.

What exactly does it do?

Mailserverports of this server are being checked by using the JavaScript-based-portscanner of GNUCITIZEN. Every listed port will be scanned 10 times. If at least 3 scans are successful, the light is green. Up to 2 sucessful scans will show a yellow light and no successful scans lead to red light. The Control ports are here for validaten of the result, since this JavaScript-portscanner is kind of experimental. Port 11111 should always be red and Port 80 should always be green.

Hints for various web browsers

  • Internet Explorer 8,11,Edge: Working fine without any configuration
  • Firefox: Working fine - Configuration required
  • Google Chrome: Working fine - Configuration required
  • Firefox

    Firefox is blocking the required ports by default. If these ports are not configured as allowed, this page wrongly indicates all ports are open. You can allow the ports doing this:
    1. Open "about:config" in your browser address bar
    2. Click right in the main page
    3. Select new > String
    4. New Property Name:
    5. New Property Value: 25,110,143,465,587,993,995

    Google Chrome

    Google Chrome also block the required ports. This site also wrongly indicates all ports are open if the blocking is not removed. You can tell chrome to allow connections to the ports by executing chrome with these command line parameter: chrome.exe --explicitly-allowed-ports=25,110,143,993,995,465,587