"Matus" == Matus UHLAR <- fantomas <uh...@fantomas.sk>> writes:
Matus> is it not. To be precise:
Matus> SRS is to be used when you accept mail for one address and re-send to
Matus> another address (in different domain/on different server).
Matus> this is not the case for backup MX.
On 18.11.21 18:28, Togan Muftuoglu wrote:
Thanks for the clarification. One more thing having the backup MX listed in
the SPF records of the domain and opendkim signing the relayed mails does not
break the validations in the primary MX when it receives mail from the backup,
correct ?
there's no reason why backup MX should be listed in SPF record. Backup MX
received mail for your domain, you'd need to list it in all other domains.
...unless it rewrites mail sender, but that's not a good idea - in that case
it's not backup MX but mail forwarder :-)
The backup MX should be listed in local exemptions for SPF checking.
DKIM has nothing to do with it, unless backup MX modifies headers or body
of the mail, in which case the backup should be exempted from DKIM checks as
long.
In standard case, backup MX should do the SPF/DKIM/DMARC checks itself, and
output from backup MX should be trusted by your mailserer.
--
Matus UHLAR - fantomas, uh...@fantomas.sk ; http://www.fantomas.sk/
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