I'm trying to configure my mail server to deliver mail to relay servers in round-robin fashion using Linux and sendmail 8.13.8.
I want to achieve the following:
Let's say I run mail.example.com as the mail server, and have relay1, relay2, relay3, and relay4 ready for actual mail delivery.
Five emails arrive to mail.example.com:
mail 1 => relay1.example.com mail 2 => relay2.example.com mail 3 => relay3.example.com mail 4 => relay4.example.com mail 5 => relay1.example.com
And so forth.
I tried to set this up by defining multiple smart hosts, but it seems like the supplementary hosts only activate if the hosts before them fail.
Clearly that isn't the way. How should this be done correctly?