Load
Balancing
Medium to large sized
companies will want to configure some
load balancing features for their
incoming mail servers. For that to
happen, the company must set up a number
of mail servers, each one with a
different IP address (actually, one can
use Network Load Balancing - NLB, or
even clustering but that's a topic for a
different article). Then new MX Records
will be added to their DNS information,
pointing to the mail servers, all with
the same priority. For example:
|
Record FQDN |
Record Type |
Record Value |
MX Pref |
|
maila.dpetri.net |
A |
192.90.1.17 |
|
|
mailb.dpetri.net |
A |
192.90.1.18 |
|
|
mailc.dpetri.net |
A |
192.90.1.19 |
|
|
mail.isp.com |
A |
212.143.25.1 |
|
|
dpetri.net |
MX |
maila.dpetri.net |
10 |
|
dpetri.net |
MX |
mailb.dpetri.net |
10 |
|
dpetri.net |
MX |
mailc.dpetri.net |
10 |
|
dpetri.net |
MX |
mail.isp.com |
100 |
Testing the MX
Record configuration
Testing the MX Record
configuration is critical especially
when configuring it for the first time
with a new ISP you don't know that well
and so on. Use NSLOOKUP or DIG or any
other DNS querying tool to make sure
your records are set straight. |
