Server Failed and Zone Expired Problems

When a slave server cannot obtain updates from its master, it logs a master unreachable message. If the problem is not corrected, the slave expires the zone and stops answering requests from clients. When that happens, users start seeing server failed messages.

Symptoms

• Masters for slave zone domain unreachable messages in syslog.

• slave zone domain expired messages in syslog.

• *** domain Can't find name: server failed messages to users.

Note that if the problem is with a slave server, some users could still be successfully obtaining DNS information from the master and thus operating without experiencing any difficulty.

Possible causes

The two most likely causes for these problems are network failure and a wrong IP address for the master in the slave's boot file.

Diagnosis and solution

• Check that the slave's configuration file contains the correct IP address for the master. Check the line:

  zone "someone" { type slave; file "somefile": master [IPaddress; }; };

Make sure that the IP address of the master matches the master's actual IP address and the address for the master specified in the hosts file. If the IP address is wrong, correct it, and then reboot the slave.

• If the master's IP address is correct, make sure the master is up and running correctly by pinging the master's IP address. For example, to ping the master at IP address 192.168.0.1, you would enter the following.

  % ping 192.168.0.1 -n 10

• If the master does not respond to the ping, make sure it is up and running properly.

• If the master is running okay, use ps to make sure it is running named. If it is not running named, reboot it.

• If the master is correctly running named, you most likely have a network problem.