I disabled sbl.spamhaus.org configured in the DNS Blacklist yesterday. It was configured to log & reject messages and was working great.
I had to different people originating emails that would not go to the users mailbox. I could see the email on the Mail Routing Events but it would say disconnected with 0 messages received. The problem is only occurring when these people originate emails. If they reply to an email then we don’t have a problem.
The email domains are from two different companies. One error is deliver time expired and the other is Error reading SMTP Packet; response to dot-stuffed message expected. These are the error messages that have told me that they receive.
I thought about opening a relay to these to companies but I would rather not do that.
Thanks for any suggestions.
Subject: sbl.spamhaus.org & problem with people orginating emails
I doubt that has anything to do with sbl.spamhaus.org, though I expect they are suffering constant DDOS attacks (as is spamcop; and it was a DDOS attack that killed dorkslayers).
If NSLOOKUP 2.0.0.127.sbl.spamhaus.org returns 127.0.0.2 and does so quickly, then it probably ain’t timing out waiting for the DNSBL check to complete.
If it does take a long time to return 127.0.0.2, or if it times out then the issue is linked to name resolution in the host OS (is your name server broken?).
Otherwise, it could be a network issue. Two suggestions.
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turn off inbound pipelining if you have it turned on (doubt that will do anything to fix this problem, but it is easy and quick to do)
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try reducing your MTU size (see this thread)
http://www-10.lotus.com/ldd/nd6forum.nsf/55c38d716d632d9b8525689b005ba1c0/1fe88add2910de9985256d380033a370?OpenDocument
Worked for me.
HTH
Chris Linfoot
Subject: Thanks
Thanks for the tips. I will try them sometime next week hopefully. I didn’t think sbl.spamhaus.org was the problem but it offered me a temporary solution.
Thanks again for your help.