LinuxQuestions.org
Welcome to the most active Linux Forum on the web.
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Networking
User Name
Password
Linux - Networking This forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.

Notices


Reply
  Search this Thread
Old 02-10-2016, 01:09 PM   #1
pi3.14
LQ Newbie
 
Registered: Dec 2015
Distribution: Debian
Posts: 29

Rep: Reputation: Disabled
CNAMEs and MX Records


Hi. I've got this situation where we have a Web site and an email service hosted by a friend of our business, but the domain and DNS is under control of our registrar. Basically, the DNS right now is just a CNAME pointing to one of their domain names. There is no MX record entries on our side, so evidently DNS lookups just use the MX records for their domain. (Testing with dig confirms this.)

I want to leave the Web hosting as is, but transfer the email hosting to our email server. My question: If I just define an MX record, but leave the CNAME as it is, will our MX records "override" theirs and do what I want? Or do I need to replace the CNAME record with an AA record?
 
Old 02-10-2016, 01:36 PM   #2
MensaWater
LQ Guru
 
Registered: May 2005
Location: Atlanta Georgia USA
Distribution: Redhat (RHEL), CentOS, Fedora, CoreOS, Debian, FreeBSD, HP-UX, Solaris, SCO
Posts: 7,831
Blog Entries: 15

Rep: Reputation: 1669Reputation: 1669Reputation: 1669Reputation: 1669Reputation: 1669Reputation: 1669Reputation: 1669Reputation: 1669Reputation: 1669Reputation: 1669Reputation: 1669
Its a bit muddy.

I'm assuming you're saying you have something like
theirdomain.com has records (e.g. "A" or "AAAA" pointing to a specific IP for their web service.
yourdomain.com has CNAME records pointing to theirdomain.com (and maybe www.yourdomain.com has CNAME to theirdomain.com or www.theirdomain.com).

If so those records say where the main domain goes.

The "MX" is a separate record type. You typically defined that as a name like mailserver.yourdomain.com then have a separate record (usually an "A" or "AAAA") that defines mailserver in the yourdomain.com zone file as a specific IP (which may or may not be the same as the one you're using in base setup for web service as well). It might be a CNAME itself but I've not done CNAMEs for these. The important thing here is you have two separate records. One is the MX that tells people what mail server name to use and another that tells people where to find that mail server name (e.g. by its IP).

Usually if you're using the Registrar's DNS setup they have place where you can update records for yourdomain.com. First you'd want to see if you have an MX record for yourdomain.com their. If so you'd change that entry to point to your mailserver name. If your mailserver name is not in the the Registrar's DNS setup for yourdomain.com then you'd also have to add that record.

How you do that at the Registrar depends on who the Registrar is but the concept is the same.

Last edited by MensaWater; 02-10-2016 at 04:05 PM.
 
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off



Similar Threads
Thread Thread Starter Forum Replies Last Post
[SOLVED] MX Records / A Records / CNAME Records - Advice Please fusion1275 Linux - Newbie 15 01-18-2011 04:06 AM
Gobal ssh:known_hosts and DNS CNAMEs brianmcgee Linux - Security 1 01-18-2011 03:17 AM
Reading caller detail records(CDR ) records eliufoo Linux - Networking 2 12-16-2008 11:31 PM
CNAMES not working in Bind 9.3.1 astender Linux - Networking 12 03-04-2006 10:19 AM
cnames or dns prob? thornton Linux - Networking 3 06-19-2004 05:08 AM

LinuxQuestions.org > Forums > Linux Forums > Linux - Networking

All times are GMT -5. The time now is 08:06 AM.

Main Menu
Advertisement
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Open Source Consulting | Domain Registration