ubuntu安装配置telnet

1. sudo apt-get install xinetd telnetd

2. 安装成功后，系统也会有相应提示：

sudo vi /etc/inetd.conf并加入以下一行 telnet stream tcp nowait telnetd /usr/sbin/tcpd /usr/sbin/in.telnetd

3. sudo vi /etc/xinetd.conf并加入以下内容：

# Simple configuration file for xinetd # # Some defaults, and include /etc/xinetd.d/ defaults { # Please note that you need a log_type line to be able to use log_on_success # and log_on_failure. The default is the following : # log_type = SYSLOG daemon info instances = 60 log_type = SYSLOG authpriv log_on_success = HOST PID log_on_failure = HOST cps = 25 30 } includedir /etc/xinetd.d

4. sudo vi /etc/xinetd.d/telnet并加入以下内容：

# default: on # description: The telnet server serves telnet sessions; it uses \ # unencrypted username/password pairs for authentication. service telnet { disable = no flags = REUSE socket_type = stream wait = no user = root server = /usr/sbin/in.telnetd log_on_failure  = USERID }

5. 重启机器或重启网络服务sudo /etc/init.d/xinetd restart

6. 使用TELNET客户端远程登录即可进行非root用户访问。

7.使用root登录：

mv /etc/securetty /etc/securetty.bak 这样root可以登录了。也可这样: 

修改/etc/pam.d/login这个文件。只需将下面一行注释掉即可。 

#auth required lib/security/pam_securetty.so 

8. 具体配制/etc/xinetd.d/telnet 

service telnet { disable =no bind =192.168.1.2 only_from=192.168.1.0/24 #上面这两行说明仅提供内部网段！ Instance =UNLIMITED Nice =0 Flags =REUSE socket_type=stream wait =no user =root #server =/usr/sbin/telnetd server =/usr/sbin/in.telnetd server_args =-a none log_on_failure  =USERID } service telnet { disable =no bind =140.116.142.196 only_from=140.116.0.0/16 no_access=140.116.32.{10,26} #上面三行设置外部较为严格的限制 instance =10 umask =022 nice =10 flags =REUSE socket_type=stream wait =no user =root #server =/usr/sbin/telnetd server =/usr/sbin/in.telnetd log_on_failure  =USERID }

9.加设防火墙iptables： 

假如想要针对192.168.0.0/24这个网段及 61.xxx.xxx.xxx这个IP进行telnet开放，可以增加下面几行规则：

/sbin/iptables -A INPUT -p tcp -i eth0 -s 192.168.0.0/24 --dport 23 -j ACCEPT /sbin/iptables -A INPUT -p tcp -i eth0 -s 61.xxx.xxx.xxx --dport 23 -j ACCEPT /sbin/iptables -A INPUT -p tcp -i eth0 --dport 23 -j DROP

10.加设防火墙/etc/hosts.allow(deny)机制：

上面开放了192.168.0.0/24这个网段，但 是假如您只想让其中的192.168.0.1~192.168.0.5进入，可以设置如下 ：

vi /etc/hosts.allow in.telnetd:192.168.0.1,192.168.0.2,192.168.0.3,192.168.0.4,192.168.0.5:allow