On CentOS and RHEL, both ship with zeroconf (zero configuration networking) its used primarily for DHCP environments but for server installs where you assign a static ip address, its still one extra ultra minor performance hit that you do not need
How to check if zeroconf is enabled?
at the command line type in
Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 192.168.1.50 0.0.0.0 255.255.255.248 U 0 0 0 eth1 10.20.1.50 0.0.0.0 255.255.255.192 U 0 0 0 eth0 169.254.0.0 0.0.0.0 255.255.0.0 U 1002 0 0 eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 1003 0 0 eth1 10.0.0.0 10.20.1.1 255.0.0.0 UG 0 0 0 eth0 0.0.0.0 192.168.1.1 0.0.0.0 UG 0 0 0 eth1
Every time networking is started, either at bootup or when you restart the network service, the zeroconf route is added to your routing table. While this is great for most, its not ideal for the rest of us.
To disable this kick ass annoying feature from making your routing table look like something a that was face rolled over you need to edit the following file
and add the following at the bottom of the file
if you are in a hurry, hate vi or just plain lazy type in
#echo NOZEROCONF=yes >>/etc/sysconfig/network
then you can either restart networking
/etc/init.d/network restart or you can reboot, which ever makes you feel all warm and fuzzy
afterwords, check the routing table again
Like magic, the zeroconf’s routes are gone