CentOS6以后要安裝rp-pppoe這個軟件，centos之前的版本是adsl-setup命令安裝。
（1）查看是否安裝
#rpm -qa|grep rp-pppoe
沒有內容輸出則沒安裝，若可以聯網使用# yum install rp-pppoe
無法聯網則：CentOS安裝盤放入光驅
掛載光盤
#mount /dev/cdrom /media
找出文件路徑
# find /media -name 'rp-pppoe*'
這個文件沒有依賴項，可以直接安裝
#rpm -ivh /media/CentOS_6.5_Final/Packages/rp-pppoe-3.10-8.el6.i686.rpm
（2）設置撥號
#whereis pppoe-setup
#/sbin/pppoe-setup
或#pppoe-setup
開始設置ADSL和DNS信息：
Welcome to the PPPoE 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
LOGIN NAME
Enter your Login Name (default root): 中國電信或者網通給你的ADSL用戶名，注意電信給的有ad打頭
INTERFACE
Enter the Ethernet interface connected to the PPPoE 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← 指定網絡接入設備，一塊網卡的情況下，一般為默認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): ← 直接按回車，接受默認設置，詢問的是，adsl連接以后，是否持續保持連接。或者是自動的斷開，在指定的時間（以秒數計算）內。多數情況下，我們希望手動的打開關閉連接。所以這里選擇默認的no。
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: 202.96.209.5 第一個DNS建議手動設置，不然可能連不上（或Enter the DNS information here: server //PPPOE撥號的輸入server即可，即動態獲得DNS）
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: 202.96.209.133 第二個DNS建議手動設置，不然可能連不上
PASSWORD
Please enter your Password: 輸入ADSL的連接密碼
Please re-enter your Password: ← 再次確認輸入ADSL的連接密碼
USERCTRL
Please enter 'yes' (three letters, lower-case.) if you want to allow
normal user to start or stop DSL connection (default yes): yes← 填入no，不允許一般用戶控制PPPoE的連接
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← 輸入0，不在這里使用防火墻
Start this connection at boot time
Do you want to start this connection at boot time?
Please enter no or yes (default no):yes← 填入yes，在系統啟動時自動連接ADSL
Accept these settings and adjust configuration files (y/n)? y← 配置信息確認無誤后，鍵入y同意設置
** Summary of what you entered **
Ethernet Interface:eth0
User name:
[root@localhost ~]# pppoe-start← 啟動ADSL pppoe連接（或# ifup ppp0 //啟動ppp0接口）
[root@localhost ~]# pppoe-status 設置完成后我們看看adsl狀態
