What is the best practice when one has to implement this sort of ruleset in postfix:
- Email sent from local domain1.com, domain2.com to example.com, example1.com ought to be relayed to smtp.external.com.
- Email sent to everyone else example.com and example1.com ought to be relayed locally
I know there is a way to do a relay filtering recipient address using transport_maps, but I do not know how to filter depending on the sender address too.
Can you help me please?? Thanks in advance