I wanted postfix to send messages through a secondary IP address (failover address, not in a cluster, just a simple manual failover) instead of the primary address on the interface.
smtp_bind_address is not possible as explained above, and inet_addresses doesn't work for binding when sending, apparently.
After playing with postfix' config around for a while, I took the alternative route
:
Code:
iptables -t nat -A POSTROUTING -o eth0 \
-s the_primary_ip_addresses \
-p tcp --dport 25 \
-j SNAT --to the_ip_address_you_want_used kinda ugly, but does the trick. Still listening on all addresses (including localhost), always sending through the chosen address
Just got to make sure it's documented somewhere....