550 Relay Errors
Posted on 2006-11-01
I'm still having a problem with this. Background:
We have a web server (www1) and a mail server (exchange 2003, mail.mydomain.com). The web server uses a 3rd party asp component to send mail (persits mail sender). When the web site sends an email, that message goes to our exchange server. I can see this in the logs:
2006-10-31 19:19:34 216.191.xxx.xxx www1.mydomain.com SMTPSVC1 BCMAIL 10.0.0.7 0 HELO - +www1.mydomain.com 250 0 58 31 0 SMTP - - - -
2006-10-31 19:19:34 216.191.xxx.xxx www1.mydomain.com SMTPSVC1 BCMAIL 10.0.0.7 0 MAIL - +FROM:+<email@example.com> 250 0 57 45 0 SMTP - - - -
2006-10-31 19:19:34 216.191.xxx.xxx www1.mydomain.com SMTPSVC1 BCMAIL 10.0.0.7 0 RCPT - +TO:+<firstname.lastname@example.org> 550 0 49 28 0 SMTP - - - -
What I don't understand, is if our mail server (mail.mydomain.com) is sending the email, why is it sendin as www1.mydomain.com? www1 is the netbios name of the web server, not a public DNS address.
I can understand the relay error if it was coming from our mail server; it wouldn't allow the web server to 'relay' through it but obviously it is. At gmail's end, I assume it looks at the name www1, queries DNS and finds 'mail' is the authoritative sender and rejects it. But why is our mail server delivering as www1?
I figured the mail sender on the web server requires authentication to send but that can't be the problem either. It is accepting the message and sending it to gmail but as www1 and gmail rejects it.
Why would our exchange server deliver the message as www1?