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550 Mail Errors

tomrwilson asked
Medium Priority
Last Modified: 2012-05-05
I'm getting 550 errors in our Exchange logs for certain external emails:

2006-10-31 19:19:34 216.191.xxx.xxx www1.mydomain.com SMTPSVC1 BCMAIL 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 0 MAIL - +FROM:+<someuser@mydomain.com> 250 0 57 45 0 SMTP - - - -
2006-10-31 19:19:34 216.191.xxx.xxx www1.mydomain.com SMTPSVC1 BCMAIL 0 RCPT - +TO:+<someguy@gmail.com> 550 0 49 28 0 SMTP - - - -

Why would gmail reject the message thinking it's a relay?  This is a valid gmail mailbox.

One thing that is odd is the 'www1'.  This email is being sent by an application on our web server.  Our mail server's proper name is mail.mydomain.com.  Why would the message appear to originate from www1.mydomain.com?

Any idears on this one?
Thanks! :)
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www1.mydomain.com does not have a valid reverse DNS address listed.  Gmail is bouncing all mail coming from a server that doesn't use reverse DNS.  have your web server relay through your exchange or have your ISP setup reverse DNS for your webserver.  reverse DNS is set at the ISP level.


Problem is, www1 is not an external DNS name.  It's the actual netbios name of the web server.  www1.mydomain.com resolves to a 10.0.1.x address.  So I can't call up our ISP and ask for a reverse lookup on 10.0.1.x.

I can have the ISP give our public web server address a reverse lookup but that means www.mydomain.com will have a reverse lookup of mail.mydomain.com.  Plus, a lookup on mail.mydomain.com will return a different external address (that of the web server) and will fail anyway.

I suppose this is because the mail is being sent by the web server itself (Persits Mail Sender component for asp) and not relayed through our own mail server.

What's my best option, trash the Persits component for something that relays?
My advise is to relay through Exchange.  There should be a way in the web server email software to use your Exchange as a smart host.  

Does your web server go out to the internet using its own private IP or a NAT address?  If it doesn't have its own public IP, but used a NAT address, then have the IP of the NAT address made to a reverse DNS.  I take it your web sever is not open to external users?

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Web server has a mapped external IP.  So it's internally but 216.191.xxx.xxx externally.  If I (or have my isp) add a reverse lookup of mail.mydomain.com to the web server's external address, would that suffice?


yes, you can have them map 216.191 to a reverse DNS.  


Great, thanks for the help!
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