Re: [PLUG] user's mail not being delivered, odd error

[Rich Freeman <r-plug@thefreemanclan.net>]

On Wed, Feb 27, 2019 at 4:04 PM Rich Kulawiec <rsk@gsp.org> wrote:
>
> This is speculative but is based on way too many years of running mail
> systems:
>
> Temporary errors like this which result in deferrals (not rejects) often
> have a root cause in DNS lookup failures.

Wait, why would you be depending on external DNS servers?  Aren't you
filtering all outgoing traffic anyway?  So, if you whitelist every
mail server you let your mailserver talk to, then why would you need
to rely on outside DNS lookups in the first place?  :)

-- 
Rich
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