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Test if SMTP is blocked from Workstation to Internet

Posted on 2009-07-16
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Last Modified: 2013-11-16
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?
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Question by:fireguy1125
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shauncroucher earned 2000 total points
ID: 24869776
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
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by:fireguy1125
ID: 24869802
Ok, so I guess it is NOT blocked, as I am getting the reply.  I will have to check our firewall settings again.

Thank you.
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