How do I
configure and test the MX Record for my
Internet Domain name?
When you want to run your
own mail server, and it does not matter
what version and make of mail server
you're using - as long as the mail
server is using SMTP as the e-mail
transfer mechanism - you'll need to
configure the MX Records for your
domain.
MX is an acronym for
Mail eXchange. MX is defined in RFC
1035. It specifies the name and relative
preference of mail servers for the zone.
MX is a DNS record used to define the
host(s) willing to accept mail for a
given domain. I.e. an MX record
indicates which computer is responsible
for handling the mail for a particular
domain.
Without proper MX
Records for your domain, only internal
e-mail will be delivered to your users.
External e-mail from other mail servers
in the world will not be able to reach
your server simply because these foreign
servers cannot tell to which server they
need to "talk" (or open a connection to)
in order to send the mail destined for
that domain.
You can have multiple MX
records for a single domain name, ranked
in preference order. If a host has three
MX records, a mailer will try to deliver
to all three before queuing the mail.
MX Records must be in
the following format:
domain.com.
IN MX
10
mail.domain.com.
The Preference field is
relative to any other MX Record for the
zone and can be on any value between 0
and 65535. Low values are more
preferred. The preferred value is
usually 10 but this is just a
convention, not a thumb rule. Any number
of MX Records may be defined. If the
host is in the domain it requires an A
Record. MX Records do not need to point
to a host in the same zone, i.e. an MX
Record can. point to an A Record that is
listed in any zone on that DNS or any
other DNS server. |