The issue was resolved after running;
service network restart
However I'm attempting to figure out what was the root cause.
I ran the following;
It seems that dns port may have stopped resolving? I don't know where to proceed from here.root@server [~]# grep xx.xx.xx.75 /var/log/messages-20150628
Jun 27 09:29:23 serverX named[53576]: no longer listening on xx.xx.xx.75#53
Jun 27 09:30:30 server named[1626]: listening on IPv4 interface eth0:1, xx.xx.xx.75#53
root@server [~]# grep xx.xx.xx.76 /var/log/messages-20150628
Jun 27 09:29:23 serverX named[53576]: no longer listening on xx.xx.xx.76#53
Jun 27 09:30:30 server named[1626]: listening on IPv4 interface eth0:2, xx.xx.xx.76#53
root@server [~]# grep xx.xx.xx.78 /var/log/messages-20150628
Jun 27 09:29:23 serverX named[53576]: no longer listening on xx.xx.xx.78#53
Jun 27 09:30:30 server named[1626]: listening on IPv4 interface eth0:4, xx.xx.xx.78#53