Solve Linux Ping: Unknown host www.baidu.com

Linux Ping: Unknown host www.baidu.com from http://www.cnblogs.com/happyhotty/articles/2539951.html

"Ping: Unknown host www.baidu.com"
Solution:
If a Linux server cannot ping the domain name, the following prompt is displayed:

[Root @ localhost ~] # Ping www.baidu.com
Ping: Unknown host www.baidu.com

First, make sure that the vro is connected and the vro can access the Internet.

[Root @ localhost ~] # Ping 192.168.1.1
Ping 192.168.1.1 (192.168.1.1) 56 (84) bytes of data.
64 bytes from 192.168.1.1: icmp_seq = 1 TTL = 64 time = 2.96 MS
64 bytes from 192.168.1.1: icmp_seq = 2 TTL = 64 time = 1.75 MS

If the network is correct, follow these steps:
1) Confirm that the Domain Name Server has been set. If not, it is recommended to set up Google's public DNS Service, which should not cause problems.


[Root @ localhost ~] # Cat/etc/resolv. conf

Search localdomain

Because my DNS is not set, the ping to the Internet fails. Add DNS to this file

[Root @ localhost ~] # Vi/etc/resolv. conf

Search localdomain
Nameserver 202.98.96.68
Nameserver 61.139.2.69
~

2) Make sure that the gateway has been set

# Grep gateway/etc/sysconfig/network-scripts/ifcfg *
-------------------------------------------------------------------
/Etc/sysconfig/network-scripts/ifcfg-eth0: Gateway = 192.168.40.1
-------------------------------------------------------------------

If not, add the gateway as follows:

# Route add default GW 192.168.40.1

You can also manually write the/etc/sysconfig/network-scripts/ifcfg * file and restart the network service:

# Service network restart

3) make sure DNS resolution is available

# Grep hosts/etc/nsswitch. conf
-------------------------------------------------------------------
Hosts: Files DNS
-------------------------------------------------------------------

If any of the above problems occurs, correct them and test them again. The problem should be solved:

# Ping-C 3 www.baidu.com
Ping www.a.shifen.com (220.181.6.175) 56 (84) bytes of data.
64 bytes from 220.181.6.175: icmp_seq = 0 TTL = 50 time = 9.51 MS
64 bytes from 220.181.6.175: icmp_seq = 1 TTL = 50 time = 8.45 MS
64 bytes from 220.181.6.175: icmp_seq = 2 TTL = 50 time = 8.97 MS
--- Www.a.shifen.com Ping statistics ---
3 packets transmitted, 3 bytes ed, 0% packet loss, Time 2002 Ms
RTT min/AVG/max/mdev = 8.450/8.977/9.511/0.446 MS, pipe 2