Solved

Redundant MX Records for Network Blips

Posted on 2008-10-17
4
566 Views
Last Modified: 2013-11-30
I have a hosted Exchange account set up for my domain through Vendor A. Vendor A has two Exchange servers, and they have end users execute "load balancing" by setting MX Records for both spam1.VENDOR A.com and spam2.VENDOR A.com to the same priority. I have the priority of both servers set to '10'.

I also have a shared web hosting package set up with Vendor B. Vendor B provides a trimmed down, POP3 mail solution to all of its clients, and I have the same addresses and aliases set up through their control panel as I do with Vendor A.

I wanted to have Vendor B set up as a redunant mailbox, in case mail was unable to be delivered to Vendor A, so I added new MX Records for Vendor B and set the priority to 30.

So, here's the catch... I went to log into the Webmail application for Vendor B, simply to show a prospective client the Roundcube interface for webmail, and I had about 7 messages in my inbox from the past week. To my knowledge, that mail should not have hit Vendor B without Vendor A being completely unreachable by the sender's mail server. Since it was routed to Vendor B, that indicates to me that the sender's mail server was unable to contact Vendor A.

So I contacted Vendor A, and they reported they've had no connectivity problems over the past 3 days... yet, clearly, someone trying to route mail to my account with them was experiencing problems connecting to them. While the redundant mail solution with Vendor B worked as a catch-all, I want to know:

Can I set up additional, duplicate MX records for Vendor A with a priority of '20', such that, if a message is unable to reach the Vendor A mail servers at priority '10', it will try them again at priority '20' before ever attempting to send to Vendor B at priority '30'? I'm hoping that, if this is possible (and depending on the timeout/retry values of the originating mail servers), that the mail will be delivered to Vendor A on the second attempt before looking at Vendor B.

Here's a mock-up of my current and intended MX Records:

CURRENT:
spam1.VENDOR A.com   -   10
spam2.VENDOR A.com   -   10
mail.VENDOR B.com        -   30

PROPOSED:
spam1.VENDOR A.com   -   10
spam2.VENDOR A.com   -   10
spam1.VENDOR A.com   -   20
spam2.VENDOR A.com   -   20
mail.VENDOR B.com        -   30

So, ultimately, the question is: Can I set duplicate MX record entries with adjacent priorities (e.g., 10 and 20, 11 and 13, etc.) such that I can force a "second-attempt" at the primary mail server before attempting to send to different, redundant mail servers? If so, how would I go about executing this? And how does this relate to / affect / hinder best practices?

Thanks!
0
Comment
Question by:prussel3
  • 2
  • 2
4 Comments
 
LVL 23

Accepted Solution

by:
Justin Durrant earned 350 total points
ID: 22743337
Yep.. that will work.. also see http://bind-users.info/mx.html
0
 
LVL 1

Author Comment

by:prussel3
ID: 22744884
While I appreciate the quick response, would you mind positing an answer to the last part of my question, just for my own reference...

How will implementing these changes affect the performance / stability of mail delivery to my domain?
0
 
LVL 23

Expert Comment

by:Justin Durrant
ID: 22745015
MX changes only provide redundancy for mail delivery to your domain.
0
 
LVL 1

Author Closing Comment

by:prussel3
ID: 31507219
Thanks again.
0

Featured Post

Are your AD admin tools letting you down?

Managing Active Directory can get complicated.  Often, the native tools for managing AD are just not up to the task.  The largest Active Directory installations in the world have relied on one tool to manage their day-to-day administration tasks: Hyena. Start your trial today.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

MS Outlook is a world-class email client application that is mainly used for e-communication globally.  In this article, we will discuss the basic idea about MS Outlook, its advanced features, and types of MS Outlook File formats.
How to resolve IMCEAEX NDRs in Exchange or Exchange Online related to invalid X500 addresses.
This video discusses moving either the default database or any database to a new volume.
In this tutorial you'll learn about bandwidth monitoring with flows and packet sniffing with our network monitoring solution PRTG Network Monitor (https://www.paessler.com/prtg). If you're interested in additional methods for monitoring bandwidt…

856 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question