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This article introduces the relevant knowledge of "what is ZEROCONF in CentOS5.x". In the operation of actual cases, many people will encounter such a dilemma. Then let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

There is a server of CentOS 5.5 (network segment is 172.21.73.0). Looking at its routing table, we find a strange item:

[shengkui@APP-SERVER ~] $route

Kernel IP routing table

Destination Gateway Genmask Flags Metric Ref Use Iface

172.21.73.0 * 255.255.255.0 U 000 eth0

169.254.0.0 * 255.255.0.0 U 000 eth0

Default 172.21.73.253 0.0.0.0 UG 0 0 0 eth0

There is an item of 169.254.0.0. What is this routing list entry for and where does it come from?

After searching for information, I finally understand that this project is: Zero Configuration Network (ZEROCONF). ZEROCONF is also called IPv4 Link-Local (IPv4LL) and Automatic Private IP Addressing (APIPA). It is a dynamic configuration protocol through which the system can connect to the network.

Many Linux distributions install this service by default, and when the system cannot connect to DHCP server, it will try to get IP through ZEROCONF.

In CentOS5.x, the routing entry for ZEROCONF is added to the routing table in the following startup script.

/ etc/init.d/network will call the / etc/sysconfig/network-scripts/ifup-eth script, and the ifup-eth script will add the ZEROCONF routing entry as follows:

# Add Zeroconf route.

If [- z "${NOZEROCONF}"-a "${ISALIAS}" = "no"-a "${REALDEVICE}"! = "lo"]; then

Ip route replace 169.254.0.0 ip route replace 16 dev ${REALDEVICE}

Fi

Is there any way to disable ZEROCONF?

You can do this by adding a line "NOZEROCONF=yes" to the "/ etc/sysconfig/network" file.

In fact, assigning an arbitrary value to NOZEROCONF has the same effect, and as you can see from the above code, it only detects whether the NOZEROCONF is empty.

Of course, after modifying "/ etc/sysconfig/network", the network must be restarted to take effect: / etc/init.d/network restart

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