Using the telnet command you can test if a port is open.
You can check if a port is open in your network by issuing the telnet command.
telnet [domainname or ip] [port]
If the port is open, you will see a blank screen. This will mean that connection is successful.
telnet relay.appriver.com 2525
In Windows Vista and Windows 7 you may need to enable telnet first:
Article ID: 572
Created On: Tue, Mar 4, 2014 at 12:29 PM
Last Updated On: Tue, Mar 4, 2014 at 12:51 PM
Authored by: Administrator [email@example.com]
Online URL: https://kb.quikbox.com/article.php?id=572