【图】linux下adsl拔号与共享上网

多台电脑通过ADSL同时上网，如果有路由，那就太简单了。但是，如果没路由只有交换机怎么办呢？一般有两种方法。

1、用双网卡（一个接内网，一个接外网）的机器装代理服务器软件（windows下有winGet等）来完成，但这种方法要两块网卡（浪费）,同时还要装代理软件（烦，而且还会被打盗版）。
2、通过共享拔号连接来解决，这种方法很简单且不需要其它的软件。

对于windows下的第二种方法的实现网上有很文章且很简单，在此不作阐述。

下面就我在linux(在centOS4.4,rhel as 4,fc5下测试通过)下如何通过adsl拔号与共享上网作一个简单的记录，希望对新手有所帮助。

1、拔号上网
1.1拔号软件
    linux下的拔号软件很多，但比较好的是rp-pppoe,一般linux系统会自带拔号软件，如果你没装，请自己到google去找一个来装上。
1.2拔号设置
    切换为root用户,只有root才能配置。
    $ su
    Password:
    # /sbin/adsl-setup
    按提示设置用户名、密码、DNS、及其它相关信息，下面是我的参考配置:
Welcome to the ADSL client setup. First, I will run some checks on
your system to make sure the PPPoE client is installed properly...

The following DSL config was found on your system:

Device: Name:
ppp0 DSLppp0

Please enter the device if you want to configure the present DSL config
(default ppp0) or enter 'n' if you want to create a new one:

Enter your Login Name (default xyn0699647):

INTERFACE

Enter the Ethernet interface connected to the ADSL modem
For Solaris, this is likely to be something like /dev/hme0.
For Linux, it will be ethX, where 'X' is a number.
(default eth0):

Do you want the link to come up on demand, or stay up continuously?
If you want it to come up on demand, enter the idle time in seconds
after which the link should be dropped. If you want the link to
stay up permanently, enter 'no' (two letters, lower-case.)
NOTE: Demand-activated links do not interact well with dynamic IP
addresses. You may have some problems with demand-activated links.
Enter the demand value (default no):

DNS

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