如何解决Linux操作系统找不到网卡的问题
1. 安装网卡
机器太新，以至于现有的Linux版本无法认出，比如机器找不到网卡，这时候怎么办呢？
别急，首先你需要知道网卡是什么型号的，以本实验室新购入的电脑为例，它的网卡是集成的，型号是Realtek RTL8168/8111 PCI-E Gigabit Ethernet NIC。然后我们到Realtek的官方网站去下载相应的Linux驱动程序r8168-8.005.00.tar.bz2，按照说明安装。
Unpack the tarball :
# tar vjxf r8168-8.aaa.bb.tar.bz2
Change to the directory:
# cd r8168-8.aaa.bb
If you are running the target kernel, then you should be able to do :
# make clean modules (as root or with sudo)
# make install
# /sbin/depmod -a
# /sbin/insmod ./src/r8168.ko (or r8168.o in linux kernel 2.4.x)
You can check whether the driver is loaded by using following commands.
# /sbin/lsmod | grep r8168(看看有没有加载网卡驱动)
# /sbin/ifconfig –a(看看有没有相关网卡被启动的信息)
If there is a device name, ethX, shown on the monitor, the linux
driver is loaded. Then, you can use the following command to activate
the ethX.
# ifconfig ethX up
,where X=0,1,2,...
这里也可以通过系统→管理→网络来设置IP地址等，最后激活。
1. Set manually
a. Set the IP address of your machine.
# ifconfig ethX "the IP address of your machine"
b. Set the IP address of DNS.
Insert the following configuration in /etc/resolv.conf.
nameserver "the IP address of DNS"
c. Set the IP address of gateway.
# route add default gw "the IP address of gateway"
2. Set by doing configurations in /etc/sysconfig/network-scripts
/ifcfg-ethX for Redhat and Fedora, or /etc/sysconfig/network
/ifcfg-ethX for SuSE. There are two examples to set network
configurations.
a. Fix IP address:
DEVICE=eth0
BOOTPROTO=static
ONBOOT=yes
TYPE=ethernet
NETMASK=255.255.255.0
IPADDR=192.168.1.1
GATEWAY=192.168.1.254
BROADCAST=192.168.1.255
2. 修改：＃vi /etc/hosts，在该文本中，增加两行：
127.0.0.1 localhost.localdomain localhost
192.168.4.101 node3（根据机器本身情况设置）
修改：vi /etc/hosts.equiv，增加一行：(如果没有该文本，可建立一个)
node3
3. 启动ssh服务
大部分的Linux版本应该都会自带该程序
＃ssh-keygen
＃cd .ssh
＃cp id_rsa.pub authorized_keys
＃ssh node3（如果成功，会显示上次登陆的时间， node3是主机名）
附加信息：
ifup eth0看看能否启动eth0
lsmod看看有没有加载网卡驱动
dmesg看看有没有网卡启动时的错误信息
