How do I prevent open relay but allow anonymous connections?

Posted on 2010-11-11
Last Modified: 2012-05-10
I have a Microsoft Exchange 2003 server on MS Windows Server 2003. My server was sending out spam. I removed the anonymous access from the Access Control and now it isn't an open relay, but it appears as though external email is not being delivered. Did I do something wrong? Thanks.
Question by:leviatdr
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LVL 35

Assisted Solution

by:Ernie Beek
Ernie Beek earned 200 total points
ID: 34116415
read this one:

You can skip the part to check if you're an open relay ;-)

Expert Comment

ID: 34116429
You need enable the anonymous access. Click the RELAY button in the Access tab and make sure ONLY THE LIST BELOW is selected and no entries exist below that.

Author Comment

ID: 34116450
When I have Anonymous Access enabled, I can telnet into my mail server and send email without authentication. I went through the article above and could not resolve my issue. What else can I check?
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Accepted Solution

vanbarsoun earned 300 total points
ID: 34116482
You will be able to send email to addresses in your domain without authentication, but not to other domains. Go here and check to see if your IP is relaying:

LVL 35

Expert Comment

by:Ernie Beek
ID: 34116550
' I went through the article above and could not resolve my issue'

How did you check?

Author Comment

ID: 34116643
I checked it by trying the commands through telnet from an external IP.

I was incorrect about being an open relay. It seems more like a compromised user account. I've enabled authentication logging, hopefully I can figure out where the bulk email came from. Anything else I should watch?

Author Closing Comment

ID: 34116656
My initial assumption was wrong. I was not a open relay. Further investigation is needed to find out why my mail server was sending out spam.

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