:-) Numerous users of my system use forward to external MTAs. From time to time it causes some issues with SPF on those MTAs. SRS could resolve those. I'm wondering if you could recommend any SRS software which nicely integrates with postfix and doesn't interfere with canonicals (postsrsd does[*]).
[*]I need to rewrite both senders' addresses (`MAIL FROM:' and `From:') for all outgoing mail with canonicals before SRS is applied. Moreover: canonical should rewrite both addresses and SRS - only envelopes, so the should not rely on the same settings (sender_canonical_classes). Best regards, Marek