Red Hat LINUX 7.2 Reference Manual page 234

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www
• MX — Mail eXchange record, which tells where mail sent to a particular namespace controlled
by this zone should go.
Figure 14–11 Sample MX record configuration
In Figure 14–11, Sample MX record configuration, the <preference-value> allows you to
numerically rank the email servers you would prefer to receive email for this namespace, giving
preference to some email systems over others. The MX resource record with the lowest <pref-
erence-value> is preferred over the others, but you can set multiple email servers with the
same value to distribute email traffic between them.
The <email-server-name> may be a hostname or FQDN, as long as it points to the correct
system.
Figure 14–12 Example MX records
In this example, the first mail.domain.com email server is preferred to the mail2.do-
main.com email server when receiving email destined for the domain.com domain.
• NS — NameServer record, which announces the authoritative nameservers for a particular zone.
Figure 14–13 Sample NS record configuration
The <nameserver-name> should be a FQDN.
In Figure 14–14, Example NS records, two nameservers are listed as authoritative for a domain.
It is not important whether these nameservers are slaves or if one is a master; they are both still
considered authoritative.
Figure 14–14 Example NS records
• PTR — PoinTeR record, designed to point to another part of the namespace.
PTR records are primarily used for reverse name resolution, as they point IP addresses back to a
particular name. See Reverse Name Resolution Zone Files in Section 14.2.2 for more examples of
PTR records in use.
IN CNAME
IN MX <preference-value>
IN MX 10
IN MX 20
IN NS <nameserver-name>
IN NS dns1.domain.com.
IN NS dns2.domain.com.
Chapter 14:Berkeley Internet Name Domain (BIND)
server1
mail.domain.com.
mail2.domain.com.
<email-server-name>