[19506] in North American Network Operators' Group
Re: RFC 974 - Mail Routing and the Domain System
daemon@ATHENA.MIT.EDU (Andrew Staples)
Wed Sep 16 02:47:40 1998
From: "Andrew Staples" <andrews@ltinet.net>
To: <nanog@merit.edu>
Date: Tue, 15 Sep 1998 23:37:29 -0700
> BIND will round robin the MX records, how mail agents deal with
>multiple MX records of the same priority is less of a known factor (to
>me at least). Actually I'd be interested to hear from people who try
>both configurations for say a month at a time to see what influence each
>configuration has if any.
RFC 974 reads:
D.EXAMPLE.ORG IN MX 0 D.EXAMPLE.ORG
D.EXAMPLE.ORG IN MX 0 C.EXAMPLE.ORG
D.EXAMPLE.ORG IN WKS 10.0.0.4 TCP SMTP
In the third example, consider a mailer on A.EXAMPLE.ORG trying to deliver a
message to D.EXAMPLE.ORG. In this case there are only two MX RRs, both with
the same preference value. Either MX will accept messages for D.EXAMPLE.ORG.
The mailer should try one MX first (which one is up to the mailer, though
D.EXAMPLE.ORG seems most reasonable), and if that delivery fails should try
the other MX (e.g. C.EXAMPLE.ORG).
