# ssh -p 2012 localhost
Password: #输入内网 Linux 主机的 SSH 密码
Last failed login: Sat Nov 3 18:10:34 CST 2012 from localhost on ssh:notty
There was 1 failed login attempt since the last successful login.
Last login: Sat Nov 3 11:31:56 2012 from localhost
Have a lot of fun...
beyes:~ #
由上可见,外网服务器通过连接本地的 2012 这个端口从而进到了内网的主机。
再看一个测试实例(假设内网主机已经开启 HTTP 服务),在内网主机上运行下面命令:
ssh -N -R 2012:127.0.0.1:80 118.118.118.118
然后在外网服务器运行下面命令:
# curl -G "http://127.0.0.1:2012" -o out.html
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
0 44 0 44 0 0 72 0 --:--:-- --:--:-- --:--:-- 0
# curl -G "http://127.0.0.1:2012" -o out.html
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 2208 100 2208 0 0 3406 0 --:--:-- --:--:-- --:--:-- 0