ssh tunnelling chain
In OpenSSH, I use this setup when I need tunnels. This allows me to directly type sftp server3
without having to worry about manually starting the server2
and server1
tunnels first.
# ~/.ssh/config# to connect to server2, tunnel through server1Host server2ProxyCommand ssh server1 nc %h %p# to connect to server3, tunnel through server2Host server3ProxyCommand ssh server2 nc %h %p
To be more complete, I usually use ssh -oCiphers=arcfour128,arcfour256,arcfour,blowfish-cbc -oControlMaster=no -oForwardX11=no -oForwardAgent=no -oPermitLocalCommand=no -oClearAllForwardings=yes server1 nc %h %p
as the ProxyCommand
.
- The ssh connection being tunneled is already encrypted, so there's no point in using the heavier
aes
/3des
for the outer layer;arcfour
andblowfish
are faster. - The rest of the
-o****
settings are out of paranoia, so that nothing breaks even if aHost server1
stanza with really odd settings is added tossh_config
.
Similarly, you can configure PuTTY to use the proxy command plink -P %proxyport -pw %pass %user@%proxyhost nc %host %port
, and set the proxy hostname/port/user/password in the Connection/Proxy configuration pane accordingly. plink
and the rest of the PuTTY suite (pscp
, psftp
, etc.) load anything saved in PuTTY's graphical configuration; hopefully WinSCP does too. (I don't use it, so I'm not too familiar with its features.)
The first solution that leaps to mind is to tunnel one local port to each of your servers. Since SSH uses port 22, we'll use each SSH connection to tunnel a local port to the next server's port 22.
When you open PuTTY, you're met with the PuTTY Configuration dialog. The two categories you'll need to edit are "Session" and "Connection→SSH→Tunnels".
Open a copy of PuTTY. Use these settings:
Connect to host
- Host name:
server1
- Port: 22
- Host name:
Tunnel a port
- Local mode
- Source port:
15500
Destination:
server2:22
(the secure shell port)
Now, every time you connect to port 15500 on your local machine, your connection is being tunneled to port 22 on server2.
Open a copy of PuTTY. Use these settings:
- Connect to host
- Host name:
localhost
- Port: 15500
- Host name:
- Tunnel a port
- Local mode
- Source port:
15501
- Destination:
server3:22
(the secure shell port)
- Connect to host
Open a copy of PuTTY. Use these settings:
- Connect to host
- Host name:
localhost
- Port: 15501
- Host name:
- Tunnel a port
- Local mode
- Source port:
15502
- Destination:
server3:22
(the secure shell port)
- Connect to host
Use WinSCP to connect to
localhost
on port15502
. Your connection will be tunneled as if you're connecting toserver3
directly.
Let me know in the comments whether this works for you. Good luck!
This method is similar to the way you can use proxycommand in the open ssh config file.
A prerequisites for this method is that Pageant must be used with public key authentication by all intermediate (proxy) hosts otherwise you will end up with a flashing cursor and nothing else. To learn more about Pageant, PuTTYgen and public keys see:
http://the.earth.li/~sgtatham/putty/0.62/htmldoc/Chapter8.html#pubkey
http://the.earth.li/~sgtatham/putty/0.62/htmldoc/Chapter9.html#pageant
We have four machines accessible in this order
PuttyPC -> server01 -> server02 -> server03
For server01 we have a Putty saved session as:
Main Window: user1@server01
// port 22
// SSH
Save this session as server01
For server02 we have a Putty saved session as:
Main Window: user2@server02
// port 22
// SSH
Proxy config window: type local
// proxy command plink -load server01 -nc %host:%port
Save this session as server02
For server03 we have a Putty saved session as:
Main window: user3@pc3
// port 22
// SSH
Proxy config panel: type local
// proxy command plink -load server02 -nc %host:%port
Save this session as server03
This means that the saved session for server03 will call the saved session for server02 and server02 saved session will call the server01 session.