Updating etc mail aliases
This avoids the need to specify firewall IP addresses into Postfix configuration files.
1 /etc/postfix/main.cf: 2 mynetworks = 127.0.0.0/8 .0/24 3 relay_domains = 4 parent_domain_matches_subdomains = 5 debug_peer_list smtpd_access_maps 6a # Postfix 2.10 and later support separate relay control and 7a # spam control.
A null client typically uses POP, IMAP or NFS for mailbox access.
At least, that is how Postfix installs when you download the Postfix source code via #myorigin = $mydomain # Optional: specify NAT/proxy external address.#proxy_interfaces = 188.8.131.52 # Alternative 1: don't relay mail from other hosts.Execute the command "newaliases" whenever you change the aliases file.The idea is to set up a Postfix email firewall/gateway that forwards mail for "example.com" to an inside gateway machine but rejects mail for "anything.example.com".
mynetworks_style = host relay_domains = # Alternative 2: relay mail from local clients only.