On Tue, Apr 22, 2025 at 01:29:53PM +1000, Viktor Dukhovni via mailop wrote:
> One likely source of problems may have been the default
> "[!UNAVAIL=return]" element of the "hosts:" entry in nsswitch.conf:
>
> hosts: files myhostname resolve [!UNAVAIL=return] dns
>
> With this, transient errors in "resolve" may be "upgraded" to hard errors.
> Since I have a local caching/validating resolver, I'm changing this to:
>
> hosts: myhostname files dns
>
> If the above best guess is correct, and others also have similar
> nsswitch.conf configurations, you should consider changing nsswitch.conf
> to ensure more reliable mail delivery (avoid erroneous hard errors).
Responding to my own messages, it seems I've been down this road before:
https://marc.info/?l=postfix-users&m=171381526626315&w=2
But, embarrasingly, my own MTA (originally FreeBSD, but more recently
Fedora) did not have the fix in place. I had only fixed the problem on
the DANE survey MX host, or, perhaps, a later update undid the fix. :-(
--
Viktor.
_______________________________________________
mailop mailing list
mailop@mailop.org
https://list.mailop.org/listinfo/mailop
