Telnet to Port 25 to Test SMTP Communication
Goto start-->run
type in cmd
click ok
telnet yourdomain.com 25
Screen shot of what is suppose to appear if 25 is not blocked.
If it is blocked it will not show anything. If this is the case you will want to contact you network administrator, ISP, or check you firewall settings(this includes setting on the windows, your DSL router, AntiVirus, Firewall, Internet secuirty software, or Zone Alarm). Note: We do not provide tech support for firewall wall settings.