Symptoms
Named will fail to start and report errors similar to the following:
/etc/named.conf:380: zone 'domain.com': already exists previous definition: /etc/named.conf:213
You may find this error being reported in /var/log/named/named.log or in /var/log/messages.
Description
This issue occurs when the named configuration has duplicate entries. It will prevent the named service from starting.
Workaround
One way to quickly resolve the issue would be to move aside the named.conf and then rebuild it:
mv -v /etc/named.conf{,.bak}
/scripts/rebuilddnsconfig