解决centos5.1不能上网的问题

说明：

1.使用的电脑安装的是双系统：xp和centos5.1

2.在xp下可以上网，但是在centos5.1下就是不能上网

3.centos5.1中，不能ping通网关。

4.xp中网卡设置为：

ip：192.168.1.57

掩码：255.255.255.0

网关：192.168.1.10

DNS：192.168.1.10

在centos5.1中查看网卡信息为：

[root@localhost ~]# ifconfig -a

eth0      Link encap:Ethernet  HWaddr 00:E0:4C:2A:2E:0C  

          inet addr:192.168.1.57  Bcast:192.168.1.255  Mask:255.255.255.0

          inet6 addr: fe80::2e0:4cff:fe2a:2e0c/64 Scope:Link

          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

          RX packets:1511 errors:0 dropped:0 overruns:0 frame:0

          TX packets:304 errors:0 dropped:0 overruns:0 carrier:0

          collisions:0 txqueuelen:0 

          RX bytes:139496 (136.2 KiB)  TX bytes:32922 (32.1 KiB)

查看网关：

[root@localhost ~]# vi /etc/sysconfig/network-scripts/ifcfg-eth0

# Realtek Semiconductor Co., Ltd. RTL8101E PCI Express Fast Ethernet controller

DEVICE=eth0

ONBOOT=yes

BOOTPROTO=none

HWADDR=00:e0:4c:2a:2e:0c

TYPE=Ethernet

NETMASK=255.255.255.0

IPADDR=192.168.1.57

GATEWAY=192.168.1.1

USERCTL=no

IPV6INIT=no

PEERDNS=yes

 

查看DNS：

[root@localhost ~]# cat /etc/resolv.conf

search localdomain

 

可以发现，原来网关和DNS不对，更改后重启网络服务：

[root@localhost ~]# service network restart

Shutting down interface eth0:                              [  OK  ]

Shutting down loopback interface:                          [  OK  ]

Disabling IPv4 packet forwarding:  net.ipv4.ip_forward = 0

                                                           [  OK  ]

Bringing up loopback interface:                            [  OK  ]

Bringing up interface eth0:                                [  OK  ]

 

[root@localhost ~]# ping 192.168.1.10

PING 192.168.1.10 (192.168.1.10) 56(84) bytes of data.

64 bytes from 192.168.1.10: icmp_seq=1 ttl=64 time=0.475 ms

64 bytes from 192.168.1.10: icmp_seq=2 ttl=64 time=0.324 ms

 

--- 192.168.1.10 ping statistics ---

2 packets transmitted, 2 received, 0% packet loss, time 999ms

rtt min/avg/max/mdev = 0.324/0.399/0.475/0.078 ms

[root@localhost ~]# ping www.baidu.com

PING www.a.shifen.com (119.75.217.56) 56(84) bytes of data.

64 bytes from 119.75.217.56: icmp_seq=1 ttl=54 time=22.8 ms

64 bytes from 119.75.217.56: icmp_seq=2 ttl=54 time=25.3 ms

64 bytes from 119.75.217.56: icmp_seq=3 ttl=54 time=25.2 ms

 

--- www.a.shifen.com ping statistics ---

3 packets transmitted, 3 received, 0% packet loss, time 1998ms

rtt min/avg/max/mdev = 22.829/24.474/25.332/1.170 ms

 

 

 

作者 xiangbei1573