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Email Issues

Posted on 2010-08-20
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Last Modified: 2012-05-10
I have a client who has been infected with the Antimalware Doctor crap.  As I was running Malwarebytes on the computer a couple of others started reporting problems with their emails.  They are reporting the following errors:

There was a SMTP communications problem with the recipients email server.

<xxxx.com #5.5.0 smtp;550 Recipient Rejected:  Access Denied: xx.xx.xx.xx blocked by composite list>

Can anyone please shed some light on the fix here?  They are using a Small Business Server 2003.
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Question by:PC4N6
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by:uescomp
ID: 33487181
You have most likely been added to a DNS blacklist because the virus was sending out spam.  You can go to MX Toolbox to check your domain and see if it is listed.  Most lists will automatically de-list you once you stop spamming, but some require a manual removal request.

http://www.mxtoolbox.com/
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DewFreak earned 500 total points
ID: 33487196
Your mail server has been blacklisted.  Go here to check and follow directions to be removed after you have cleaned up all the infected workstations:

http://cbl.abuseat.org/

Also to check more blacklists go here:

http://mxtoolbox.com/blacklists.aspx
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by:aoakeley
ID: 33490048
uescomp and DewFreak re correct. As well as (before even) getting of the lists you MUST ensure your network is clean. If you get re-listed it is harder to get off the lists on the second or third time around...

Make some changes to your firewall (router?) so that only the SBS server is allowed outgoing connections on port 25. This will ensure ony the SBS Server can directly send email, and reduce the chance that an infected workstation will send spam and get you re-listed.
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