TCP/IP Configuration and Management Manual

Configuration Reference
TCP/IP Configuration and Management Manual—427132-004
A-20
Domain Name Server Files
An example for setting up a mail list is as follows:
Bind IN MINFO Bind-Request kjd.BigCityU.Edu.
IN MG Ralph.BigCityU.Edu.
IN MG Zhou.BigCityU.Edu.
IN MG Painter.BigCityU.Edu.
IN MG Riggle.BigCityU.Edu.
IN MG Terry.pa.XYZCorp.Com.
MX—Mail Exchanger
The format of this record is:
name [ttl] addr-class MX preference-value mailer-exchanger
For example:
Miller.OY.AB. IN MX 0 Seismo.ESS.GOV.
*.IN. IN MX 0 RELAY.ES.NET.
The Mail Exchanger (MX) record specifies a machine that knows how to deliver mail to
a machine that is not directly connected to the network. In the first example,
Seismo.ESS.GOV. is a mail gateway that knows how to deliver mail to Miller.OY.AB.,
but other machines on the network cannot deliver mail directly to Miller. These two
machines may have a private connection or use a different transport medium. The
preference-value is the order that a mailer should follow when more than one way
exists to deliver mail to a single machine. Refer to RFC 974 for more detailed
information on preference values.
You may use wildcard names containing an asterisk (*) for mail routing through MX
records. The network is likely to include servers which simply state that any mail sent
to a domain is to be routed through a relay. In the second example, all mail to hosts in
the domain *.IN is routed through RELAY.ES.NET. This routing is accomplished by
creating a wildcard resource record, which states that *.IN has an MX of
RELAY.ES.NET.