How to round robin MX records properly

Is this the correct way to round robin the MX records:

10   example.com   xxx.xxx.xxx.111
10   example.com   xxx.xxx.xxx.222

or should it always be via priority levels:

10   example.com   xxx.xxx.xxx.111
20   example.com   xxx.xxx.xxx.222

Note: The mail servers in both IP address are simply forwarding emails (email accounts doesn't have it's own mailbox) so my goal is to just keep the mails forwarded in the event that one of the servers goes down.

What would be the proper approach?

IMB

Posted 2014-01-24T15:59:29.610

Reputation: 4 845

2The first one is the correct. The rfc defines that the priorities are in decreasing preferences. So in order to do a round robin they should be the same everywehre. It is another story how the resolver will chose one of them but should be fine anyways. – zeridon – 2014-01-24T16:02:19.273

Answers

If you want the servers to behave in a round robin fashion then setting the priority levels equal to each other is the correct way to achieve this. There is nothing wrong with this if both servers serve the same purpose.

So if you had:

10    example.com    192.168.1.1
10    example.com    192.168.1.2
20    example.com    192.168.1.3

The mail server sending the message would try either one of the 10 records first, then try the other, then try the 20 record if the first two failed.

Google Apps has its mx records set up in a similar fashion.

Alex McKenzie

Posted 2014-01-24T15:59:29.610

Reputation: 1 559