Currently if user of server A mails B@parabola.nu which is forwarded to server C, A has SPF records not allowing mail sent from repo.parabolagnulinux.org and C uses SPF to reject mail, that mail will be rejected.

We need to use SRS to rewrite envelope sender addresses for mails to parabola.nu that we forward, and to verify and rewrite addresses that get bounces for them.

https://github.com/roehling/postsrsd would do it, but canonical maps get only the sender address, while we need the recipient domain (parabola.nu) to decide if we want to rewrite the address. I haven't found a way to make postfix rewrite addresses only with specific recipient domains.

Other possible solutions:

• patch postfix * make parabola.nu virtual aliases deliver to a command that rewrites addresses and mails postfix, add aliases for bounce addresses that use another command; is there an existing implementation of such a command or should we write our own (preferably using libsrs2)? (mailman uses this interface for forwarding list mails to subscribers)