> On Jul 29, 2019, at 10:30 AM, Дилян Палаузов via Exim-dev <exim-dev@???> wrote:
>
> I guess, that a site publishing many MX records pointing to many IP addresses is not an additional option to increase
> the retry rate.
RFC-compliant MTAs accept at least 100 recipients per transaction.
RFC-compliant sending MTAs limit the number of recipients to at
most 100 per envelope, sending additional recipients in separate
envelopes, thus avoiding the need for retries.
Some too-big-to-fail receiving systems violate the required minimum
recipient limit, forcing legitimate bulk senders to tweak their
systems in ad-hoc ways. That does not make it generally a good
idea to do that.
If you're operating a receiving system, accept at least 100
recipients per envelope, and just 2 to 4 MX host are quite
enough. Having 50 MX IP addresses just makes your system
look like a snowshoe spam farm, and serves no useful purpose.
--
Viktor.
