I have faced a network connection problem, when looking into messages logs using tail command received some error output

#  tail -f /var/log/messages

Jun 23 12:06:46 host3 named[939]: error (network unreachable) resolving 'ns3.domain.com/AAAA/IN': 192.228.79.201#53
Jun 23 12:06:46 host3 named[939]: error (network unreachable) resolving 'ns2.domainname.com.cn/A/IN': 203.119.27.1#53
Jun 23 12:06:46 host3 named[939]: error (network unreachable) resolving 'serverhost.NET/AAAA/IN': 2001:dc3::35#53

by default, named try to listen IPv6 even if there is no IPv6 configured on the host. So you need to add a line end of named file /etc/sysconfig/named
 
vim /etc/sysconfig/named

OPTIONS="-4"

Save and exit from the file:
 
:wq!

Finally, restart named services.
 
# /etc/init.d/named restart
Stopping named: ...        [  OK  ]
Starting named:            [  OK  ]