Re: New SRS patch

> SRS is really a transformation that is tied to the SMTP protocol.
I agree, SMTP would be a better place to transform the sender.

> This could be addressed by making smtp_generic_maps more general,
> such that there are separate variants for envelope sender, envelope
> recipient, and likewise the message header addresses (perhaps with
> names like smtp_sender_envelope_generic_maps, etc.)

Extending smtp_generic_maps is nice, but won't help in this situation. 
A lookup table isn't sufficient to do the rewriting, we need a function 
like postfix_srs_forward (in analogy to verp_sender).

I don't quite understand the DSN problem. If the envelope recipient is 
a srs address, the message is most likely a bounce. Are there any cases 
where someone is interested in DSNs of bounces?

> Does the SRS patch rewrite the headers as well as the envelope?
No, headers aren't touched in SRS.