Print Page | Close Window

mx-records

Printed From: LogSat Software
Category: Spam Filter ISP
Forum Name: Spam Filter ISP Support
Forum Description: General support for Spam Filter ISP
URL: https://www.logsat.com/spamfilter/forums/forum_posts.asp?TID=5429
Printed Date: 02 June 2025 at 7:39pm


Topic: mx-records
Posted By: Guests
Subject: mx-records
Date Posted: 27 December 2005 at 11:21am

How does two mx-records work?

If I have mx10 and mx20, sending mailserver should first try mx10 and if that doesn't work it should try mx20.

But what if I have mx10 and mx10, does the sending mailserver try the other one if the first one is failing?

thanks,

Web123


Replies:
Posted By: LogSat
Date Posted: 27 December 2005 at 3:45pm
The simplest way to answer is by posting the following quote from Section 5 of RFC 2821:

   Multiple MX records contain a preference indication that MUST be used
   in sorting (see below).  Lower numbers are more preferred than higher
   ones.  If there are multiple destinations with the same preference
   and there is no clear reason to favor one (e.g., by recognition of an
   easily-reached address), then the sender-SMTP MUST randomize them to
   spread the load across multiple mail exchangers for a specific
   organization.





-------------
Roberto Franceschetti

http://www.logsat.com" rel="nofollow - LogSat Software

http://www.logsat.com/sfi-spam-filter.asp" rel="nofollow - Spam Filter ISP


Print Page | Close Window