Internal networks
As stated above, there is
usually no need to configure MX Records
for internal use, simply because
internal (i.e. inter-organization)
e-mail and replication traffic is
usually controlled via Active
Directory-store information. However
there are some cases where you will want
to configure internal MX Records.
While these MX Records
will generally not cause any harm even
if you configure them without actually
needing them, you must pay close
attention to various configuration
issues, especially when Mail-Relays and
Smart-Hosts are involved. Therefore I
cannot say for sure if configuring
non-necessary MX Records will cause any
problems to your local network. If you
do not know for sure (and this might be
the case since you've bothered to read
this article in the first place) I
suggest you consult a network specialist
before doing any changes.
Fault Tolerance
In case your mail server
fails you'd like to still be able to
receive incoming e-mail messages. Most
small to medium sized companies will pay
their ISPs some monthly fee and that
will buy them storage space on the ISPs
mail servers. For that to happen, a new
MX Record will be added to their DNS
information, pointing to the ISPs mail
server with a higher priority. For
example:
Record FQDN |
Record Type |
Record Value |
MX Pref |
mail.dpetri.net |
A |
192.90.1.17 |
|
mail.isp.com |
A |
212.143.25.1 |
|
dpetri.net |
MX |
mail.dpetri.net |
10 |
dpetri.net |
MX |
mail.isp.com |
100 |
|