Lost E-mail (Solved)

kwebdesign · Unread post by **kwebdesign** » Tue May 20, 2008 9:25 am

Alright, all you geniuses out there - can you help me out with this problem?

I've got a client who says they are not getting any e-mail from a specific e-mail address, which is generated by an automated system via one of their partners. They are getting other e-mails from that partner, but one specific set of e-mails from a specific address are not coming through.

In digging through the logs, I see connections coming from the partner (via relaylock messages in maillog) about every 15 minutes. However, I only see messages actually being delivered about 4-6 times per day, and never from the e-mail address in question.

I've added the partners domain to my whitelists (both in Spamassassin config and in the Plesk mail config), and I've verified that they are not listed in any of the RBL's I'm using. I've also set Spamassassin to archive SPAM instead of deleting it, and checked the mailbox after a few days, but there are no messages there.

What's the next step to figuring out what's happening when they connect to my SMTP port every 15 minutes? A sniffer? Are there any other logs I should be looking at?

My suspicion is that my server is rejecting their mail attempt for some reason, but they are never seeing the error message because it's generated by some automated system that doesn't capture errors. I'm trying to get more info on the system that's generating the e-mails and what the headers, etc. should look like. I just wanted to do whatever I could on my end to investigate as well.

Any advice is appreciated. Thanks.

kwebdesign · Unread post by **kwebdesign** » Tue May 20, 2008 10:07 am

Never mind - I figured it out.

I used tcpdump to watch the transaction, and it was the old bare LF problem (http://cr.yp.to/docs/smtplf.html). Apparently, they are not capturing the response sent by my server to their malformed e-mails.