Troubleshooting DNS

After configuration, DNS starts automatically if /etc/inet/named.conf is present. When named starts up, it writes its process id to the file /etc/inet/named.pid. This is useful to programs that want to send signals to named.

If you encounter problems with named, first view the logfile /var/adm/log/osmlog for any errors. If none are found, use the kill(1) command to send signals to named. This allows you to troubleshoot DNS without restarting the named process. Useful commands are:

kill -HUP `cat /etc/inet/named.pid`

Causes named to read named.conf and reload the database, overwriting cached data. This is useful when you make a change to a data file and you want named's internal database to reflect the change.

This command also has the effect of scheduling all slave servers for serial-number checks, which could lead to zone transfers ahead of the usual schedule. Normally, serial-number comparisons are done only at the intervals specified in the zone's SOA record.

kill -INT `cat /etc/inet/named.pid`

Dumps the current database and cache to /var/tmp/named_dump.db. This gives you an indication to whether the database was loaded correctly.

kill -USR1 `cat /etc/inet/named.pid`

Turns on debugging. Each following invocation of this command increments the debug level. The output goes to /var/tmp/named.run.

kill -USR2 `cat /etc/inet/named.pid`

Turns off debugging completely.

kill -WINCH `cat /etc/inet/named.pid`

Toggles tracing of all incoming queries. The trace is sent to /var/adm/log/osmlog and provides a large amount of data.