> Your description is too sketchy. Please choose appropriate domain
> names under example.com, example.net, example.org, ... (if the real
> domain names are sensitive) that make it clear what sender and
> recipient addresses look like in each direction.
>
> You should be able to the right thing with transport_maps, but specific
> guidane requires a less vague description.
My apologies, I try to be more detailed.
2 organisations in 2 private networks.
2 private DNS setups in both organisations, completely independant from each
other.
Mail between the 2 organisations is routed via MX lookups which point to our
Postfix.
organisation A has the following MX records in its own DNS:
@A1.example.com
@B1.example.com <- points to our postfix
organisation B has the following MX records in its own DNS:
@B1.example.com
@B2.example.com
@A1.example.com <- points to our postfix
The postfix host uses the DNS in organisation A and has a multi instance setup.
The first instance routes only mail from A to B. It uses
smtpd_sender_restrictions=reject_unknown_sender_domain and relays all mail to a
relayhost.
Everything is fine with this instance.
The second instance routes only mail from B to A. Destination lookups are done
via A´s DNS.
Everything is fine with mail from senders in @B1.example.com to recipients in
@A1.example.com.
The problem rises with mail originating from senders in @B2.example.com to
recipients in @A1.example.com.
Because the destination server in A also does a
smtpd_sender_restrictions=reject_unknown_sender_domain and @B2.example.com is
unknown in A´s DNS the sender address is rejected.
The missing MX Record in A´s DNS is ok, because senders in @B2.example.com are
not supposed to participate mail exchange with @A1.example.com and vice versa.
But where to deliver the bounce?
The postfix host uses A´s DNS and the transport_maps are not complete due to
not allowed zone transfers from some DNS servers in B.
I tried sender_dependent_relayhost_maps but because it only works on the
envelope sender, locally and remotely bounces are treated equally.
My end-goal if possible is: distinguish between remotely and locally generated
bounces and send locally generated bounces to a relayhost which can deliver the
bounce to recipients in @B2.example.com.
Can this behavior somehow be accomplished or must I go through the prcoess of
log file analysis to identify the missing record @B2.example.com in
transport_maps?
Peter
