So, you want to use an ssh tunnel, to get to another ssh tunnel? Here is how to create and use it.
SSH Tunnel through Tunnel Command
Nothing new here, but I documented it in case I forget:
ssh -t L7070:localhost:7071 user@jumphost ssh -t -D7071 user@furtherhost
Explanation of SSH Tunnels
SSH is a secure protocol and you can put data inside of it that would otherwise be sniffed, viewed, intercepted etc. When you use an ssh tunnel you simply direct your application (like firefox) to use the tunnel as a proxy instead of using the IP networking that the operating system offers.
Very much like the SSH Tunnel Tutorial which uses a socks proxy (and this one can too), the above command will open port 7070 on your local machine to the jumphost, from the jumphost port 7071 it routes it outbound to the ssh server on furtherhost.
All you need to do to use this SSH tunnel is point your application to the localhost on port 7070 and your ip will appear to come from the furtherhost, not the jumphost.
What Does localhost Port Usage Look Like?
I’m using firefox socks proxy function:
C:\Users\james\desktop>tasklist | findstr fire firefox.exe 7796 Console 1 754,212 K C:\Users\james\desktop>netstat -ano Active Connections Proto Local Address Foreign Address State PID ... TCP 127.0.0.1:50008 127.0.0.1:50009 ESTABLISHED 7796 TCP 127.0.0.1:50009 127.0.0.1:50008 ESTABLISHED 7796 TCP 127.0.0.1:55603 127.0.0.1:7070 ESTABLISHED 7796 TCP 127.0.0.1:55633 127.0.0.1:7070 ESTABLISHED 7796 TCP 127.0.0.1:56279 127.0.0.1:7070 ESTABLISHED 7796 ...
What Does FurtherHost Port Usage Look Like?
I’m browsing gmail through the tunneled tunnel:
(1:226)# netstat -ano Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State Timer tcp 0 0 127.0.0.1:3306 0.0.0.0:* LISTEN off (0.00/0/0) tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN off (0.00/0/0) tcp 0 0 126.96.36.199:34536 188.8.131.52:443 ESTABLISHED off (0.00/0/0) tcp 0 0 184.108.40.206:34540 220.127.116.11:443 ESTABLISHED off (0.00/0/0) tcp 0 0 18.104.22.168:34535 22.214.171.124:443 ESTABLISHED off (0.00/0/0) ...
(1:227)# nslookup 126.96.36.199 Server: 188.8.131.52 Address: 184.108.40.206#53 Non-authoritative answer: 220.127.116.11.in-addr.arpa name = qh-in-f100.1e100.net.
What is My Final Apparent IP?
Testing on whatismyip.com and through my apache acls shows that the ip is 18.104.22.168 (my furtherhost example).