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AIX sendmail can't do SMTPAUTH - emails bouncing

4:40 pm on Oct 29, 2014 (gmt 0)

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I have a situation where a client was on an old hosting system. They moved to a new cpanel hosting system.

They have an internal AIX based server that was using SMTP to send emails to people in the office with attached PDFs. That worked until we moved to the new hosting.

Cpanel was bouncing the emails because the AIX sendmail was sending it as Root@localmachinename.domain.local. I don't believe that the dns can be used to authenticate the origin of the emails in that case.

My opinion is that cpanel was rightly refusing these emails. We can't do a mail relay through our domain because cpanel requires a user id/pw verification.

Am I correct in assuming that emails sent this way will be undeliverable to a certain number of recipients?

I did find a solution where we could set up an email relay with a service that will authentic based on the static ip of the internal server. That would work.

The enterprise system vendor is claiming that the problem is with our hosting.. I'm contending that the problem is that the way they are sending the emails from the aix smtp not showing as a domain that can be reversed in the dns will result in a lot of the emails bouncing.

I'd appreciate any thoughts.


1:50 am on Oct 30, 2014 (gmt 0)

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WebmasterWorld Senior Member lammert is a WebmasterWorld Top Contributor of All Time 10+ Year Member Top Contributors Of The Month

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Cpanel is not an email system. It is a control panel which provides a graphical user interface to services running at a lower level. If I remember correctly, Cpanel uses exim as the default SMTP service. Exim is capable of accepting and rerouting emails from fixed IPs, even if those clients were not authenticated using SMTPAUTH. This is done in the configuration with access control lists [exim.org].

The exim access control lists can be edited with the Cpanel basic editor [documentation.cpanel.net]. Be sure that you only add the AIX host to the list and check afterwards that you didn't create an open relay accidentally.
3:25 am on Oct 30, 2014 (gmt 0)

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Lammert - Thanks for the reply. I'll take a look at that.