"ping: unknown host www.baidu.com"
解决方案：
如果某台Linux服务器ping不通域名, 如下提示:
# ping www.baidu.com
ping: unknown host www.baidu.com
如果确定网络没问题的情况下, 可以通过如下步骤寻找解决办法:
1) 确定设置了域名服务器, 没有的话, 建议设置Google的公共DNS服务, 它应该不会出问题的
# cat /etc/resolv.conf
-------------------------------------------------------------------
nameserver 8.8.8.8
nameserver 8.8.4.4
-------------------------------------------------------------------
2) 确保网关已设置
# grep GATEWAY /etc/sysconfig/network-scripts/ifcfg*
-------------------------------------------------------------------
/etc/sysconfig/network-scripts/ifcfg-eth0:GATEWAY=192.168.40.1
-------------------------------------------------------------------
如果未设置, 则通过如下方式增加网关:
# route add default gw 192.168.40.1
或者手工编写/etc/sysconfig/network-scripts/ifcfg*文件后, 重启network服务:
# service network restart
3) 确保可用dns解析
# grep hosts /etc/nsswitch.conf
-------------------------------------------------------------------
hosts: files dns
-------------------------------------------------------------------
如果以上哪个有问题, 修正后, 再测试, 应该就没问题了:
#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 received, 0% packet loss, time 2002ms
rtt min/avg/max/mdev = 8.450/8.977/9.511/0.446 ms, pipe 2