Solution to CentOSDNSresolv restart failure

A CentOS6.2 instance was installed in the previous week and the IP address was manually assigned. DNS is set in/etc/resolv. conf. Then you can access the Internet. After the machine is restarted, the website can be pinged. open/etc/resolv. conf and you will find that it is not tested again. The original direct modification of/etc...

A CentOS 6.2 IP address was manually assigned to the ECS instance and DNS was set in/etc/resolv. conf. Then you can access the Internet. After the machine is restarted, the website can be pinged. open/etc/resolv. conf and you will find that it is not tested again.

It turns out that you cannot directly modify/etc/resolv. conf. You must add the dns settings in/etc/sysconfig/network-scripts/ifcfg-eth0. Otherwise, after the restart, you must use the eth0 settings without dns information to restore/etc/resolv. conf to the original state.

Vim/etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE = eth0
BOOTPROTO = none
HWADDR = 00: xx: 19: xx
ONBOOT = yes
TYPE = Ethernet
USERCTL = no
IPV6INIT = no
PEERDNS = yes
NETMASK = 255.255.255.0
IPADDR = xxx. xxx
GATEWAY = xxx. xxx
DNS1 = 202.96.209.5 # Shanghai dns, changed according to the actual situation
DNS2 = 202.96.209.20.# Shanghai dns, changed according to the actual situation

In this case, you do not need to set it in/etc/resolv. conf.
After service network restart, we can find that there are two dns resolution ip addresses in/etc/resolv. conf.

Cat/etc/resolv. conf

Generated by NetworkManager
Nameserver 202.96.209.5
Nameserver 202.96.209.20.
Search localdomain

DNS resolution settings are successful.
It should be emphasized that/etc/resolv is directly modified. conf file is useless, the network service will restart according to/etc/sysconfig/network-scripts/ifcfg-eth0 to reload the configuration, if the ifcfg-eth0 does not configure DNS, then resolv. conf will be washed out and then become a null value.

Well, I don't know why this has not happened to the previously installed system?

Modify the host file
Open the host file

/Etc/hosts

Add the required items in the following format:

Format:

.

Example:

216.239.37.99 www.2cto.com

After editing, you need to restart your network.

/Etc/init. d/networking restart