http over ssh
很多时候，出于对安全的考虑，我们只能通过SSH 22端口访问服务器，或者有加密传输数据的需求，我们需要通过SSH tunnel来传输数据
接下来的内容，介绍了怎样通过SSH tunnel来实现HTTP服务的访问。
具体情况：
webserver是我们要访问的服务器，user是用户名
如果我们的本地机是linux/unix，通常用命令行搞定，在本地机的shell里输入下面命令，并登录
[code]
ssh -L 8000:localhost:80 user@webserver
[/code]
然后使用本机的浏览器访问 https://localhost:8000，就可以访问webserver的http服务
这条命令建立了一个ssh tunnel，看下man
[plain]
-L [bind_address:]port:host:hostport
Specifies that the specified port on the local (client)
host is to be forwarded to the specified host and port
on the remote side. This works by allocating a socket to
listen to the port on the local side, optionally bound
to the specified bind_address. Then, whenever a connec-
tion is made to this port, the connection is forwarded
over the secure channel and a connection is made to host
port hostport from the remote machine. Port forwardings
can also be specified in the configuration file. Only a
user with enough privileges can forward privileged
ports. IPv6 addresses can be specified with an alterna-
tive syntax: [bind_address/]port/host/hostport or by
enclosing the address in square brackets.
By default, the local port is bound in accordance with
the GatewayPorts setting. However, an explicit
bind_address can be used to bind the connection to a
specific address. The bind_address of localhost
indicates that the listening port be bound for local use
only, while an empty address or * indicates that the
port should be available from all interfaces.
[/plain]
这条命令建立了，本地的8000端口，到，locahost(相对webserver的localhost，也就是webserver)80端口的绑定。
当访问localhost:8000端口时，数据会通过ssh加密，传输到webserver，然后webserver会把ssh接收到的数据，传输给自身的80端口
当然，如果要以webserver为跳板，访问webserver2的80端口也是可行的，只需
[code]
ssh -L 8000:webserver2:80 user@webserver
[/code]
这种情况，多用于，webserver可以通过ssh访问，而webserver2和webserver在同一网络，但是webserver2我们不能直接访问，则用webserver作为跳板就可以通过https://localhost:8000来访问webserver2的服务。
windows下多用putty和secureCRT来搞定
参考 https://oldsite.precedence.co.uk/nc/putty.html
在登录webserver之前，配置tunnel，不要忘记点击add，然后open，登录，ssh tunnel就建立起来了
secureCRT版本
评论