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Cannot send e-mail to a specific domain

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7 replies

by p-barrett

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When ever I try and send an e-mail from my linux external mail server with a registered domain name, to my exchange server with another registered domain name I get the following error:

The following addresses had transient non-fatal errors

----- Transcript of session follows -----

Deferred: Connection refused by .
Warning: message still undelivered after 4 hours
Will keep trying until message is 5 days oldI can send from the exchange IMS to the linux server no problem and I can recieve on the exchange from anywhere else.....any ideas from anyone would be a great help, as I am really unfamiliar with Linux. I am running sendmail v 8.8.7, but I do not know which release of Linux it is (ie RedHat or Mandrake ect....) I think it is just a generic Linux.

7 replies

by stillatit

The message means that when the linux server tried to connect to the Exchange server on port 25 to deliver the messages, the Exchange server refused the connection.

This is most likely to be that the Exchange server tried to validate your linux server and failed. Is there a reverse DNS entry for the linux box? Does your Exchange server have any special validation rules for connecting servers? Is the linux box looking up your (Exchange server) domain via the MX record and finding the wrong box?

Good luck.

by admin

I'm guessing you may have Small Business Server, but not sure. If this doesn't work, give me more info on your OS and Exchange version.
Exchange server does not natively use POP3 for incoming mail. You have to get the POP3 connector from Microsoft and point it at your Linux box with sendmail.
Basically, if your isp's or other mail servers communicate with SMTP, everything is ok. But Sendmail uses POP3 and this must be translated to IMS and SMTP.

Here's the MS story:
http://www.microsoft.com/TechNet/sbs/tools/getstart.asp

by eresquigal

On a generic internet machine, if you type "host ip-of-linux-box", does it give you back the fqdn of the linux box ?

If it doesn't you are probably hitting the anti-spam protection on the exchange server (it may do a reverse lookup to see if you really are who you say you are).

If your IP is dynamic (dial, cable, etc ...) and your ISP doesn't accept DNS updates on the reverse maps, some machines will refuse to accept mail from your box.

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