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find workstations on network causing blacklist

Posted on 2013-05-28
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hi,
I suspect i have a workstation on our network that is sending out spam, because we keep getting blacklisted.

I have verified our Server (running exchange 2003) is not causing the issue, so it must be a workstation.

Whats some good ways to determine which workstation is causing the problem?

I could install pcap on all workstations and use wireshark to check but installing pcap on 100 workstations seems like a bad idea.
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Question by:Brad Nelson
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Manpreet SIngh Khatra earned 2000 total points
ID: 39203405
Look there isnt a simply way to track a machine for being compromised its check with it though

You can use EXMON to try and check which machine\user is getting high CPU constantly and then check them.
You can also enable NCSA logging for Email-flow and then check it. You can also enable Jounaling for sometime (Only if Enterprise)

- Rancy
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by:deroode
ID: 39203796
Usually you should be able to get a report from the company blacklisting you about why you are blacklisted. If they don't provide that, it would be smarter to check the internet traffic at the point where it gets to the internet, e.g. place a hub (yes, they still exist) between your network switch and your internet router, hook up a workstation on that hub and install Wireshark. That way you can see all traffic between your workstations and the internet.

Furthermore, make sure your exchange server doesn't serve as an open relay. Even if it does not send loads of spam, being an open relay will get you blacklisted.

Try http://www.mailradar.com/openrelay/ to test your service.
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