while true; do nc -z localhost 3333 >|/dev/null || (ssh -NfL 3333:REMOTE_HOST:5432 USER@REMOTE_HOST); sleep 15; done

Keep SSH tunnel open (PostgreSQL example)

Check if SSH tunnel is open and open it, if it isn't. NB: In this example, 3333 would be your local port, 5432 the remote port (which is, afaik, usually used by PostgreSQL) and of course you should replace REMOTE_HOST with any valid IP or hostname. The example above let's you work on remote PostgreSQL databases from your local shell, like this: psql -E -h localhost -p 3333

By: rxw
2015-09-21 02:25:49

These Might Interest You

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  • This command will: 1. open an SSH tunnel to 2. go to background 3. wait for 10 seconds for the connection 4. during the 10 seconds wait it will localy run 'rdesktop' to connect to the remote host through the created SSH tunnel. Password-less log in can be achieved (when server allows it) by adding '-p ' to the 'rdesktop' command

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    johnquail · 2011-07-14 05:48:06 0
  • In a multiple PostgreSQL server environment knowing the servers version can be important. Note that psql --version returns just the local psql apps version which may not be what you want. This command dumps the PostgreSQL servers version out to one line. You may need to add more command line options to the psql command for your connection environment. Show Sample Output

    psql -h <SERVER NAME HERE> -c 'SELECT version();' | grep -v 'version\|---\|row\|^ *$' | sed 's/^\s*//'
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  • - port 8080 on localhost will be a SOCKSv5 proxy - at localhost:localport1 you will be connected to the external source server1:remoteport1 and at bind_address2:localport2 to server2:remoteport2 - you will be using only IPv4 and arcfour/blowfish-cbc, in order to speed up the tunnel - if you lose the connection, autossh will resume it at soon as possible - the tunnel is here a background process, wiithout any terminal window open

    autossh -M 0 -p 22 -C4c arcfour,blowfish-cbc -NfD 8080 -2 -L localport1:server1:remoteport1 -L bind_address2:localport2:server2:remoteport2 user@sshserver
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  • Uses ssh as tunnel tunnel for an other connection. -f runs ssh in the background -N tell that there is no command to run -L deals with the forwarding aspect where the first number is the local port number, the second is parameter is the name of the server to forward to and the third parameter is the port number on that server. The last part of the command is the usual ssh form consisting of the user name and remote server name

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  • Autossh maintains a Tunnel opened. This example adds connectivity through a HTTP Proxy

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What Others Think

OK, I can see this would be useful. A poor man's VPN. This would be OK if ssh kept crashing, but a if your connection's intermittent, a better alternative might be to enable: ClientAliveInterval, ClientAliveCountMax man 5 sshd_config
flatcap · 138 weeks and 5 days ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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