CentOS下撥號上網（網絡轉載）

一、確實pppoe軟件包已經安裝
rpm -qa|grep rp-pppoe

二、運行 adsl-setup 命令，會出現相關提示，根據提示輸入賬號，密碼，還有DNS服務器地址即可：

[ root@sysconfig ~ ] # 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...


LOGIN NAME

Enter your Login Name (default root): B401    (需要輸入的賬號，我這裏輸B401爲例)



然後進入下一個提示：

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):                 (需要選擇進行撥號的網卡，我這裏使用默認的Eth0，按回車即可)    

然後進入下一個提示：


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):        （這一步選擇默認的no即可，回車）


然後進入下一個提示：輸入第一個DNS服務器地址，


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     （我這裏輸入的是廣州的DNS服務器地址）

然後進入下一個提示：輸入第二個DNS服務器地址，

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: 8.8.8.8 （我這裏輸入的是轉發DNS服務器地址）

然後進入下一個提示：輸入密碼，再確認輸入一次，


PASSWORD

Please enter your Password:
Please re-enter your Password:

然後進入下一個提示：

USERCTRL

Please enter 'yes' (three letters, lower-case.) if you want to allow
normal user to start or stop DSL connection (default yes):
                        （這一步選擇默認的yes即可，回車）

然後進入下一個提示：

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): 0    （這一步選擇是否啓用防火牆，我這裏不使用，輸入0）


然後進入下一個提示：
Start this connection at boot time

Do you want to start this connection at boot time?
Please enter no or yes (default no):   （這一步選擇是否開機自動啓用，我這裏不使用，回車即可）


然後進入下一個提示：
** Summary of what you entered **

Ethernet Interface: eth0
User name:          B401
Activate-on-demand: No
Primary DNS:        202.96.134.133
Secondary DNS:      8.8.8.8
Firewalling:        NONE
User Control:       yes
Accept these settings and adjust configuration files (y/n)? y
                （這一步選擇是否確認交運行此配置，我這裏輸入y啓用，）

Adjusting /etc/sysconfig/network-scripts/ifcfg-ppp0
Adjusting /etc/resolv.conf
  (But first backing it up to /etc/resolv.conf.bak)
Adjusting /etc/ppp/chap-secrets and /etc/ppp/pap-secrets
  (But first backing it up to /etc/ppp/chap-secrets.bak)
  (But first backing it up to /etc/ppp/pap-secrets.bak)



Congratulations, it should be all set up!

Type '/sbin/ifup ppp0' to bring up your xDSL link and '/sbin/ifdown ppp0'
to bring it down.
Type '/sbin/adsl-status /etc/sysconfig/network-scripts/ifcfg-ppp0'
to see the link status.

到此，已完成設置adsl上網功能。在/etc/sysconfig/network-scripts/這個目錄下會生成ifcfg-ppp0的文件。

[ root@sysconfig ~ ] # adsl-status        （查看adsl狀態）

[ root@sysconfig ~ ] # adsl-stop           (關閉adsl連接）

[ root@sysconfig ~ ] # adsl-start         （啓用adsl連接）

[ root@sysconfig ~ ] # adsl-connect       （連接adsl上網）