Resource Records

Resource Records are defined by RFC 1035 (and augmented by others). Resource Records describe global properties of a zone and the hosts or services that are part of the zone. They are described in detail in Chapter 8. Resource Records have a binary format, used internally by DNS software and when sent across a network e.g. zone updates, and a text format which is used in zone files.

Resource Records include SOA Record, NS Records, A Records, CNAME Records, PTR Records, MX Records.

Example of Resource Records in a Zone File

foo.com.      IN      SOA   ns.joe.com. root.foo.com. (
                              2003080800 ; se = serial number
                              3h         ; ref = refresh
                              15m        ; ret = update retry
                              3w         ; ex = expiry
                              3h         ; min = minimum
                              )
              IN      NS      ns1.foo.com.
              IN      MX  10  mail.anotherdomain.com.
joe           IN      A       192.168.254.3
www           IN      CNAME   joe 

For a description of what they mean or to see various sample configurations.