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Comment by rsync | Hacker News Reader

Did you know that you can do this:

  ssh -t user@machineB ssh user@machineA

That is, you can execute an ssh client command, over ssh. The '-t' option is required.

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The -t creates a terminal on the remote host, so in essence it is the same as SSH'ing to machineB and then running the ssh command.

Even cooler is the use of SSH tunneling to set up a ProxyCommand.

To expand on this, the reason why it’s “even cooler” is because you can use keys to login (as opposed to password) without forwarding your ssh-agent (which is a security risk).

I wrote more about this technique at https://michael.stapelberg.de/Artikel/ssh-conditional-tunnel...

In a nutshell:

    Host home
        Hostname home.zekjur.net
        ProxyCommand ssh -4 dualstack -W %h:%p

Then, “ssh home” will log into “home.zekjur.net” via an IPv4 connection through “dualstack”. This is useful in environments where you don’t have IPv6 and your only use-case is SSH'ing home.

For the folks who are interested in such things: "SSH, The Secure Shell: The Definitive Guide" is an amazing book with lots of great info and nice tricks/SSH solutions

http://shop.oreilly.com/product/9780596008956.do

Why would you recommend this over -W?

ssh -W user@jumpHost user@destination

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