I believe you want “sender_canonical_maps” (and “recipient_canonical_maps” if you want inbound mail to be translated backwards):
http://www.postfix.org/postconf.5.html#sender_canonical_maps
I believe you want “sender_canonical_maps” (and “recipient_canonical_maps” if you want inbound mail to be translated backwards):
http://www.postfix.org/postconf.5.html#sender_canonical_maps