A Slave Server

To set up a slave server, copy the /etc/named.conf file from the master server to the slave server, replacing the type master statement with type slave. Remove any zones that the slave server will not be acting as a slave for, including the root (.) zone, if the slave server will not respond to recursive queries. Create the /var/log/bind directory for log files as explained at the end of the previous section.

notify statement

Slave servers copy zone information from the primary master server or another slave server. The notify statement specifies whether you want a master server to notify slave servers when information on the master server changes. Set the (global) value of notify in the Options section or set it within a Zone section, which overrides a global setting for a given zone. The format is

notify YES | NO | EXPLICIT

YES causes the master server to notify all slaves listed in NS resource records for the zone as well as servers at IP addresses listed in an also-notify statement. When you set notify to EXPLICIT, the server notifies servers listed in the also-notify statement only. NO turns off notification.

When you start named, it copies the zone files to /var/named. If you specify notify YES on the master server, the zone files on the slave server will be updated each time you change the serial field of the SOA resource record in a zone. You must manually distribute changes to the /etc/named.conf file.