Wietse Venema: > Bauer, Stefan (IZLBW Extern): > > Dear Developers/Users, > > > > We want to load balance mails from the intranet to the > > postfix-relayserver-farm for outgoing traffic. Can we abuse > > A-records to load-balance in the same way MX-records have been > > designed? > > Yes, if the sender is Postfix. Postfix will randomly select from > equal-preference IP addresses and IP protocols. This is intentional, > so that mail does not get stuck when one path is broken.
Primary references: http://www.postfix.org/postconf.5.html#smtp_randomize_addresses http://www.postfix.org/postconf.5.html#smtp_address_preference Also of interest: http://www.postfix.org/postconf.5.html#smtp_mx_address_limit http://www.postfix.org/postconf.5.html#smtp_mx_session_limit > Other MTAs may use a different approach, For example, they may try > only one IP address per MX record, or they may try IPv4 only after > they fail to deliver mail over IPv6. > > Wietse >
