====== SRS ======

SPF, SRS,
Proxmox Mailgateway and SPF

When using backup MX (or PMG as relay) and mail server doesn't know if relay/PMG is "trusted" then SPF will fail
because mail is received from relay IP not sender SPF IP.

As workaround for problem there is [[https://en.wikipedia.org/wiki/Sender_Rewriting_Scheme|SRS ''Sender Rewriting Scheme'']]

===== SRS in PMG =====

<code bash>
apt install postsrsd
</code>

Configure ''SRS_DOMAIN'' in ''/etc/default/postsrsd''

<file ini /etc/pmg/templates/main.cf.in>
sender_canonical_maps = tcp:127.0.0.1:10001
sender_canonical_classes = envelope_sender
recipient_canonical_maps = tcp:127.0.0.1:10002
recipient_canonical_classes = envelope_recipient
</file>