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 SRS ''Sender Rewriting Scheme''

SRS in PMG

apt install postsrsd

Configure SRS_DOMAIN in /etc/default/postsrsd

/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