您正在看的Linux|Unix是:在Linux中安装两块网卡网络不通的解决方法。 案例一

一天，小王突然急匆匆的来找我，他说：“我在机子上刚装的redhat怎么老也ping不通服务器，我网卡的驱动都安装了，ping 自己的两块网卡的IP都能通，可就时访问不了服务器。我输入http://172.31.0.101就提示‘当试图与172.31.0.101联系时，连接被拒绝’”

我来到小王的机器前查看了一下网络配置。

[root@rhas root]# ifconfig -a

eth0 Link encap:Ethernet HWaddr 00:D0:B7:C6:8F:1D

inet addr:172.31.0.200 Bcast:172.31.0.255 Mask:255.255.255.0

UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1

RX packets:16 errors:0 dropped:0 overruns:0 frame:0

TX packets:5 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:1000

RX bytes:1306 (1.2 Kb) TX bytes:210 (210.0 b)

Interrupt:10 Base address:0xe800 Memory:d9100000-d9100038

eth1 Link encap:Ethernet HWaddr 00:01:03:40:A4:15

inet addr:172.31.0.201 Bcast:172.31.0.255 Mask:255.255.255.0

UP BROADCAST MULTICAST MTU:1500 Metric:1

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

TX packets:32 errors:0 dropped:0 overruns:0 carrier:32

collisions:0 txqueuelen:1000

RX bytes:0 (0.0 b) TX bytes:1920 (1.8 Kb)

Interrupt:11 Base address:0xec00

lo Link encap:Local Loopback

inet addr:127.0.0.1 Mask:255.0.0.0

UP LOOPBACK RUNNING MTU:16436 Metric:1

RX packets:1430 errors:0 dropped:0 overruns:0 frame:0

TX packets:1430 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:0

RX bytes:143776 (140.4 Kb) TX bytes:143776 (140.4 Kb)

[root@rhas root]# route -n

Kernel IP routing table

Destination Gateway Genmask Flags Metric Ref Use Iface

172.31.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1

172.31.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1

169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth1

127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo

0.0.0.0 172.31.0.254 0.0.0.0 UG 0 0 0 eth1

到这一步我猜想网线可能没有插到默认网关对应的网卡上即eth1(嗨！小王的机器被镶在桌子里不太好挪动。连他自己把网线插在那块卡上都不知道了。)

接着我在一机子上ping 172.31.0.200和172.31.0.201,在小王的机器监听

[root@rhas root]# tcpdump

tcpdump: listening on eth0

19:32:29.109283 172.31.0.101 > 172.31.0.200: icmp: echo request (DF)

19:32:30.109337 172.31.0.101 > 172.31.0.200: icmp: echo request (DF)

19:32:31.109418 172.31.0.101 > 172.31.0.200: icmp: echo request (DF)

19:32:42.670162 172.31.0.101 > 172.31.0.201: icmp: echo request (DF)

19:32:43.670218 172.31.0.101 > 172.31.0.201: icmp: echo request (DF)

19:32:44.670291 172.31.0.101 > 172.31.0.201: icmp: echo request (DF)

........................

........................

19:32:56.671040 172.31.0.101 > 172.31.0.201: icmp: echo request (DF)

19:32:57.671064 172.31.0.101 > 172.31.0.201: icmp: echo request (DF)

19:32:58.671133 172.31.0.101 > 172.31.0.201: icmp: echo request (DF)

19:32:59.671187 172.31.0.101 > 172.31.0.201: icmp: echo request (DF)

19:33:00.671257 172.31.0.101 > 172.31.0.201: icmp: echo request (DF)

19:33:01.671349 172.31.0.101 > 172.31.0.201: icmp: echo request (DF)

19:33:02.671377 172.31.0.101 > 172.31.0.201: icmp: echo request (DF)

19:33:03.671441 172.31.0.101 > 172.31.0.201: icmp: echo request (DF)

36 packets received by filter

0 packets dropped by kernel

没有回应，看一下Firewall的设置。

[root@rhas3 123]# iptables -L -n

Chain INPUT (policy ACCEPT)

target prot opt source destination

Chain FORWARD (policy ACCEPT)

target prot opt source destination

Chain OUTPUT (policy ACCEPT)

target prot opt source destination

又不是防火墙的问题，想了一下，我越发肯定刚才的想法是正确的。

[root@rhas root]# cat /etc/modules.conf

alias eth0 e100

alias eth1 3c59x

alias sound-slot-0 via82cxxx_audio

post-install sound-slot-0 /bin/aumix-minimal -f /etc/.aumixrc -L >/dev/null 2>&1 || :

pre-remove sound-slot-0 /bin/aumix-minimal -f /etc/.aumixrc -S >/dev/null 2>&1 || :

alias usb-controller usb-uhci

[root@rhas root]#mii-tool

eth0: negotiated 100baseTx-Fd flow-control, link ok

eth1: no linkk

找到原因了，果然是插反了。既然不方便换端口最简单的就把eth1即3Com网卡宕调就OK了

当然也可以把两块网卡分配在不同的网段。

[root@rhas root]# vi /etc/sysconfig/network-scripts/ifcfg-eth1

# 3Com Corporation|3c905C-TX/TX-M [Tornado]

DEVICE=eth1

BOOTPROTO=static

BROADCAST=172.31.0.255

HWADDR=00:01:03:40:A4:15

IPADDR=172.31.0.201

NETMASK=255.255.255.0

NETWORK=172.31.0.0

ONBOOT=no

TYPE=Ethernet~

~

~

"/etc/sysconfig/network-scripts/ifcfg-eth1" [已转换] 10L, 207C 9,1 全部

或者在启动哦时根本不要加载3Com网卡的驱动哦。

从启动我们的网络

[root@rhas root]# service network restart

正在关闭接口 eth0： [ 确定 ]

关闭环回接口： [ 确定 ]

设置网络参数： [ 确定 ]

弹出环回接口： [ 确定 ]

弹出界面 eth0：

[ 确定 ]

[root@rhas root]#

[root@rhas root]#

[root@rhas root]#

[root@rhas root]# ifconfig

eth0 Link encap:Ethernet HWaddr 00:D0:B7:C6:8F:1D

inet addr:172.31.0.200 Bcast:172.31.0.255 Mask:255.255.255.0

UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1

RX packets:68 errors:0 dropped:0 overruns:0 frame:0

TX packets:10 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:1000

RX bytes:5560 (5.4 Kb) TX bytes:504 (504.0 b)

Interrupt:10 Base address:0xe800 Memory:d9100000-d9100038

lo Link encap:Local Loopback

inet addr:127.0.0.1 Mask:255.0.0.0

UP LOOPBACK RUNNING MTU:16436 Metric:1

RX packets:2041 errors:0 dropped:0 overruns:0 frame:0

TX packets:2041 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:0

RX bytes:209184 (204.2 Kb) TX bytes:209184 (204.2 Kb)

[root@rhas root]# ping 172.31.0.101

PING 172.31.0.101 (172.31.0.101) 56(84) bytes of data.

64 bytes from 172.31.0.101: icmp_seq=0 ttl=64 time=0.542 ms

64 bytes from 172.31.0.101: icmp_seq=1 ttl=64 time=0.270 ms

--- 172.31.0.101 ping statistics ---

2 packets transmitted, 2 received, 0% packet loss, time 1004ms

rtt min/avg/max/mdev = 0.270/0.406/0.542/0.136 ms, pipe 2

[root@rhas root]# route -n

Kernel IP routing table

Destination Gateway Genmask Flags Metric Ref Use Iface

172.31.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0

169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0

127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo

0.0.0.0 172.31.0.254 0.0.0.0 UG 0 0 0 eth0

[root@rhas root]#

此时访问网络没有问题，故障排除。

案例二

由此我又想相类似的案例，一win98用户错将”TCP/IP-->拨号适配器”设置了IP，结果造成他ping不通其他机器。

e.g.将拨号适配器设置ip=172.31.0.1

C:\>ipconfig/all

Windows 98 IP Configuration

Host Name . . . . . . . . . : R4U2L8

DNS Servers . . . . . . . . :

Node Type . . . . . . . . . : Broadcast

NetBIOS Scope ID. . . . . . :

IP Routing Enabled. . . . . : No

WINS Proxy Enabled. . . . . : No

NetBIOS Resolution Uses DNS : No

0 Ethernet adapter :

Description . . . . . . . . : PPP Adapter.

Physical Address. . . . . . : 44-45-53-54-00-00

DHCP Enabled. . . . . . . . : No

IP Address. . . . . . . . . : 172.31.0.1

Subnet Mask . . . . . . . . : 255.255.255.0

Default Gateway . . . . . . :

Primary WINS Server . . . . :

Secondary WINS Server . . . :

Lease Obtained. . . . . . . :

Lease EXPires . . . . . . . :

1 Ethernet adapter :

Description . . . . . . . . : Intel(R) PRO PCI Adapter

Physical Address. . . . . . : 00-D0-B7-C6-8F-1D

DHCP Enabled. . . . . . . . : No

IP Address. . . . . . . . . : 172.31.0.200

Subnet Mask . . . . . . . . : 255.255.255.0

Default Gateway . . . . . . :

Primary WINS Server . . . . :

Secondary WINS Server . . . :

Lease O