这是我从赛迪网Linux专区中转载的一篇关于如何在RadHat系统中正确配置ADSL服务的文章，现介绍给那些学Linux的初学者。
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本文用注视加命令行提示的方式从安装实例的角度为初学linux的朋友阐述了Red Hat中用ADSL拨号上网的详细过程，希望可以给遇到此困难的朋友以帮助。
首先应该确定您是否安装了pppoe的应用程序。如果确实已经安装了，可以在终端用 adsl－setup命令启动adsl配置，提示过程为英文。大概为:
[root@localhost root]# adsl-setup
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: ppp0 //默认为ppp0
LOGIN NAME
Enter your Login Name (default SJ00411210A1): anthrax //这里用你自己的用户名代替我的anthrax:)
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): eth0 //默认网卡设备为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): no //这里使用默认no就可以了，断线后不自动拨号。
DNS
Please enter the IP address of your ISP's primary DNS server.If your ISP claims that 'the server will provide dynamic DNS addresses',enter 'server' (all lower-case) here. If you just press enter, I will assume you know what you are doing and not modify your DNS setup. Enter the DNS information here: 202.96.134.133 //主DNS地址设置，根据您的具体情况替换。
Please enter the IP address of your ISP's secondary DNS server.
If you just press enter, I will assume there is only one DNS server.
Enter the secondary DNS server address here: 202.96.134.133 //第二DNS地址设置。
PASSWORD
Please enter your Password: //这里设置密码，和unix规则一样，密码并不回显，因此不要认为您的键盘出了毛病:)
Please re-enter your Password:
//确认密码
USERCTRL
Please enter 'yes' (two letters, lower-case.) if you want to allow normal user to start or stop DSL connection (default yes): yes //是否允许普通用户共享ADSL。
FIREWALLING
Please choose the firewall rules to use. Note that these rules are very basic. You are strongly encouraged to use a more sophisticated firewall setup; however, these will provide basic security. If you are running any servers on your machine, you must choose 'NONE' and set up firewalling yourself. Otherwise, the firewall rules will deny access to all standard servers like Web, e-mail, ftp, etc. If you are using SSH, the rules will block outgoing SSH connections which allocate a privileged source port.
The firewall choices are:
0 - NONE: This script will not set any firewall rules. You are responsible for ensuring the security of your machine. You are STRONGLY recommended to use some kind of firewall rules.
1 - STANDALONE: Appropriate for a basic stand-alone web-surfing workstation
2 - MASQUERADE: Appropriate for a machine acting as an Internet gateway for a LAN
Choose a type of firewall (0-2): 1 //配置防火墙等级，根据您的需要选择。
Start this connection at boot time
Do you want to start this connection at boot time?
Please enter no or yes (default no):no //是否允许开机自动加载，这里选择no，否则系统启动速度太慢!
** Summary of what you entered **
Ethernet Interface: eth0
User name: username
Activate-on-demand: No
Primary DNS: 202.96.134.133
Secondary
DNS: 202.96.134.133
Firewalling: STANDALONE
User Control: yes
Accept these settings and adjust configuration files (y/n)?
选择y，配置完成。您可以用 adsl－start命令启动，可以用adsl－stop命令停止。
为了方便，可以在桌面建立一个应用程序链接，命令就使用adsl－start。这样每次双击那个快捷图标就可以建立adsl链接了，跟windows中一样方便。
好了，现在就开始您的网络之旅吧。(技巧:如果依据本文内容操作扔不能链接网络，可以尝试在"系统设置－>网路"中删除当前的网卡，重新配置adsl项。)
