[CentOS] ssh port forwarding

Thu Jul 12 20:15:50 UTC 2012
We Are Here <support at wearehere.net>

At 19:15 12/07/2012, you wrote:

Hi Doug,

>Thanks for the feedback Tim.
Glad I could help.

>Using your string, I can now telnet to port 22222 on localhost (hostA) and
>I get the mysql connection string (from hostB), but it is not able to make
>a mysql connection (using mysql -u user -p -h localhost --port=22222 from
>hostA), with a test user that I set up to allow connections from anywhere.
>The error that I am getting is:
>ERROR 2002 (HY000): Can't connect to local MySQL server through socket
>'/var/lib/mysql/mysql.sock' (2)
>I did test and the mysql test user that I created is able to connect from
Because the mysql connection is via an ssh tunnel, you need to ensure 
on the MySQL server hostB
that is allows the mysql user access from on hostB as that 
is effectively where the MySQL
server on hostB sees the connection coming from.

>Also, when I do this, it still opens up an ssh session, logging me into the
>remote machine, thus making it so I can't use this terminal.
Yes you need to run it is a screen session if you want it permanently 

>The eventual goal is to do this in a script, that will open the connection,
>use it for the duration of the script, and then close it when the script
>finishes, but it looks like that won't work, since it is logging me into
>the remote machine. I guess I could get around that by always leaving the
>screen session going with the connection, but I would prefer only creating
>the connection when I need it.
>Any ideas how to do this without leaving the connection open all the time?
I have used an expect script to do this in the past.  Which allows 
you to remotely log in to a server.
Downside is you need to store the password in plain text in the 
expect script.  So make sure only
root can read the script.  Or setup a lower privilege user to use 
sudo and do it that way.

regards Tim
Tim D'Cruz