James D. Parra:
> Hello,
>
> How can I drop external messages with a return address from our domain?
Something like this will reject "local" senders from outside "mynetworks".
Not tested:
# Pass mail from inside mynetworks, reject senders
/etc/postfix/main.cf:
smtpd_sender_restrictions =
permit_mynetworks,
check_sender_access hash:/etc/postfix/sender_access,
# Also matches subdomains of example.com by default (see
# parent_matches_subdomains documentation).
# Needs "postmap /etc/postfix/sender_access" after change.
/etc/postfix/sender_access:
example.com REJECT Bad sender address - you are not example.com
Wietse
