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Use of FallbackMXhost (sendmail 8.12.10)

The Alliance
Occasional Contributor

Use of FallbackMXhost (sendmail 8.12.10)


Are there any "gotchas" I need to be aware of in using the FallbackMXhost option of sendmail? It does not function at all when activated. A message such as shown below I would expect to be queued on the FallbackMXhost
however these messages are queued locally. Is there something off in my configuration to cause this option not to work? Any help you can provide will be greatly appreciated. My goal is offset the queue on the main mail
hub to the FallbackMXhost.

I have attached a portion of my file.

Message expected to queue on fall back system
Feb 3 10:01:47 dz1 sendmail[21214]: i13FBsim018410:to=, delay=00:49:25, xdelay=00:01:17, mailer=esmtp, pri=213608, [], dsn=4.0.0, stat=Deferred: Connection timed out with
Steven E. Protter
Exalted Contributor

Re: Use of FallbackMXhost (sendmail 8.12.10)

Dear Alliance,

I see no problem with this configuration.

You are going to need to test this to be sure it works right.

Steven E Protter
Owner of ISN Corporation
Geoff Wild
Honored Contributor

Re: Use of FallbackMXhost (sendmail 8.12.10)

I don't think you can achieve what you want (if I understand what it is you want that is).

"If specified, the fallbackhost acts like a very low priority MX on every host. MX records will be looked up for this host, unless the name is surrounded by square brackets. This is intended to be used by sites with poor network connectivity. Messages which are undeliverable due to temporary address failures (e.g., DNS failure) also go to the FallbackMXhost."

Why no just setup two mail servers with equal priorities? MX 10 for both?

Or buy a Network Load Balancer and place your mail servers behind it....


Proverbs 3:5,6 Trust in the Lord with all your heart and lean not on your own understanding; in all your ways acknowledge him, and he will make all your paths straight.