LINUX 连不起网提示无法连接

、安装rp-pppoe

到 http://www.roaringpenguin.com/pppoe/#download下载最新版rp-pppoe 的源代码。

tar xzvf rp-pppoe-3.5.tar.gz

然后进入解压生成的目录：

cd rp-pppoe-3.5

cd src

接下来就是常规的配置编译和安装，一切按默认的即可：

./configure

make

make install

至此，安装结束，下面是设置过程。

二、设置

1．配置你的网卡，运行：ifconfig eth0

不要给这个网卡（连接ADSL modem的网卡）设置IP地址，另外也不要设置成启动系统时激活网卡。

2．运行adsl-setup#adsl-setup

Welcome to the Roaring Penguin ADSL client setup. First, I will run some checks on your system to make sure the PPPoE client is installed properly... Looks good! Now, please enter some information:

USER NAME

>>>Enter your PPPoE user name (default XXX): 在这里输入ADSL的用户名

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 ethn, where 'n' is a number. (default eth0):如果一张网卡就设置写上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):不用写什么

DNS

Please enter the IP address of your ISP's primary DNS server. If your ISP claims that 'the server will provide 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:在这里写上主用DNS地址：202.106.0.20

下一个备用DNS地址是202.106.196.115 //这里是北京CNC的DNS服务器地址，你可以根据你所在的区域设置不同的DNS服务器地址。

PASSWORD

>>>Please enter your PPPoE password:输入密码

>>>Please re-enter your PPPoE password:再输入一次

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 setuphowever, 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):这里添写为2

** Summary of what you entered **

Ethernet Interface: eth0

User name: XXX

Activate-on-demand: No

DNS: Do not adjust

Firewalling: MASQUERADE

>>>Accept these settings and adjust configuration files (y/n)?

3．查看/etc/ppp/pap-secrets，里面应该有你刚才设置的账号和密码（密码是＊）。

4．编辑/etc/ppp/pppoe.conf

ETH=eth1 将eth1改为eth0（如果你只有一个网卡的话） USER=bxxxnxnx@sympatico.ca 将bxxxnxnx@sympatico.ca改为你刚才设置的ADSL账号 别的不要动。

5．查看/etc/resolv.conf

nameserver xxx.xxx.xxx.xxx （应该是你设置的第一DNS地址）

nameserver xxx.xxx.xxx.xxx （应该是你设置的第二DNS地址）

6．运行adsl-connect &连接，期间可以查看你的链接状态：adsl-status

1、修改/etc/ssh/sshd_config文件：

[root@qstarlx /]# vi /etc/ssh/sshd_config　 ← 用vi打开ssh的配置文件

#protocol 2,1　← 找到此行将行头“#”删除，再将行末的“,1”删除，只允许ssh2方式的连接

↓

protocol 2　← 修改后变为此状态，仅使用ssh2

#serverkeybits 768　← 找到这一行，将行首的“#”去掉，并将768改为1024

↓

serverkeybits 1024　← 修改后变为此状态，将serverkey强度改为1024比特

#permitrootlogin yes 　← 找到这一行，将行首的“#”去掉，并将yes改为no

↓

permitrootlogin no 　← 修改后变为此状态，不允许用root进行登录

#passwordauthentication yes　← 找到这一行，将yes改为no

↓

passwordauthentication no　← 修改后变为此状态，不允许密码方式的登录

#permitemptypasswords no　 ← 找到此行将行头的“#”删除，不允许空密码登录

↓

permitemptypasswords no　 ← 修改后变为此状态，禁止空密码进行登录

保存退出！

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