Question : Test if SMTP is blocked from Workstation to Internet

We had an issue with a trojan/virus infected PC generating e-mail from it over our network.  Our IP as a result got blacklisted.  Since then we pulled the PC off the network, and believe the issue to be isolated.  As a precaution I blocked all outgoing SMTP traffic to the WAN except our e-mail server.  How can I test a workstation to make sure that SMTP is being successfully blocked?

Answer : Test if SMTP is blocked from Workstation to Internet

telnet to a mail server outside your organisation.

Open command prompt

type:   telnet gmail-smtp-in.l.google.com 25


If this gives you 220 mx.google.com ESMTP 7si412080eyg.24 then 25 is NOT blocked.

It should say Connect Failed!

Shaun