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Old 05-28-2014, 08:46 PM   #1
lleb
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possible to daisy chain ssh into single command?


I know this may sound a bit silly, but I was playing around with executing a command via ssh and starting trying to ssh from server A into server B and then into C all on a single command?

ex:

Code:
$ ssh userB@serverB 'ssh userC@serverC'
this presented me with the expect p/w prompt for server B, but failed to execute the ssh into server C. I also tried with -t, but that was definitely not what i am looking for.

im not even sure this is doable, so thanks in advance.
 
Old 05-28-2014, 09:03 PM   #2
evo2
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Hi,

the ProxyCommand directive is good for this. Eg in your ~/.ssh/config
Code:
Host serverC
  User userC
  ProxyCommand ssh -qax serverB /usr/bin/nc %h %p

Host serverB
  User userB
Then from serverA as userA you can get to serverC as userC with the following command:
Code:
ssh serverC
HTH,

Evo2.

PS. If the ssh on serverA is new enough you don't need to use netcat. Instead the ProxyCommand line can be
Code:
ProxyCommand ssh -qax -W %h:%p serverB
Check the ssh man page for the -W option.
 
2 members found this post helpful.
Old 05-28-2014, 09:03 PM   #3
GaWdLy
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It's doable by bash somewhat, but even moreso by Expect. I don't know of any way to just "daisy-chain" the commands without a script being used, though (I'm far from an expert, though).
 
Old 05-28-2014, 11:55 PM   #4
lleb
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Original Poster
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Quote:
Originally Posted by evo2 View Post
Hi,

the ProxyCommand directive is good for this. Eg in your ~/.ssh/config
Code:
Host serverC
  User userC
  ProxyCommand ssh -qax serverB /usr/bin/nc %h %p

Host serverB
  User userB
Then from serverA as userA you can get to serverC as userC with the following command:
Code:
ssh serverC
HTH,

Evo2.

PS. If the ssh on serverA is new enough you don't need to use netcat. Instead the ProxyCommand line can be
Code:
ProxyCommand ssh -qax -W %h:%p serverB
Check the ssh man page for the -W option.
now that is some powerful stuff. many thanks. +1 mate.
 
  


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