You can point the A record for aaa.com to one IP and the MX record for it to
another.
I.e.
aaa IN A 192.168.1.1
IN MX 10 192.168.1.2
All the MX record does is tell the world what mail host to use for a given
domain. So you may have a web server running on aaa.com but not your email
server. When someone queries aaa.com the A record is normally returned, but if
the type is set to MX then the MX record is returned instead.
In the example above, a web page to http://aaa.com would go to 192.168.1.1,
whereas an SMTP server would connect to 192.168.1.2.
Be sure that you update the PTR records for the hosts when you change them...
...Kevin
--
Kevin Miller
Network/email Administrator, CBJ MIS Dept.
155 South Seward Street
Juneau, Alaska 99801
Phone: (907) 586-0242, Fax: (907) 586-4588 Registered Linux User No: 307357
-----Original Message-----
From: owner-postfix-us...@postfix.org [mailto:owner-postfix-us...@postfix.org]
On Behalf Of Doug Hardie
Sent: Thursday, November 16, 2017 1:32 PM
To: Postfix users
Subject: Mail Routing Question
I have a domain, say: aaa.com for which I receive mail. Currently I have A
records in DNS for aaa.com and mail.aaa.com as well as a MX record for aaa.com.
All three of them point to the same IP address which is where postfix is
running. There is a political issue with the A record for aaa.com and it
"needs" to be changed to elsewhere. I somehow seem to recall that there are
some MTAs that do not use the MX records, but only check the A records. Will
changing the A record for aaa.com cause the loss of some incoming mail?
-- Doug
