Re: [gentoo-user] SSH question

[Mick]

On Monday 20 Aug 2012 12:35:06 David Relson wrote:
> On Mon, 20 Aug 2012 06:50:29 +0100
>
> Mick wrote:
> > On Monday 20 Aug 2012 04:48:40 Canek Peláez Valdés wrote:
> > > On Sun, Aug 19, 2012 at 10:31 PM, David Relson
> > > <relson@×××××××××××××.com>
> >
> > wrote:
> > > > G'day,
> > > >
> > > > I've volunteered to do some data entry for my local bike club.
> > > > This involves a java application (jar  file) and a tunnel to a
> > > > mysql server.  I have detailed PuTTY configuration instructions
> > > > but haven't yet succeeded in converting them to ssh options.
> > > >
> > > > The configuration options include:
> > > >     Seconds between keepalives -- 120
> > > >     Don't start a shell or command
> > > >
> > > >     Forwarded port:
> > > >         source port number - PORT
> > > >         Destionation: MACHINE.DOMAIN.COM
> > > >
> > > >     Host - IP_Address
> > > >     Login - userid
> > > >     Password - pw
> > > >
> > > > Using "ssh -N userid@IP_Address" gives me a password prompt and no
> > > > command prompt - both good.
> > > >
> > > > How do I specify the forwarded port?
> > >
> > > If I understand correctly, with -L:
> > >
> > > ssh -L XX:machine2:YY user@machine1
> > >
> > > This command will connect you to the "machine1" host with user
> > > "user", and any connection to the port XX to the machine you are
> > > running the ssh command from, will redirect the connection to the
> > > "machine2" host in the YY port.
> >
> > If you want to forward a local port XX to a remote port YY then
> > Canek's suggestion will do what you want, assuming that the correct
> > remote application is listening on port YY.
> >
> > When you have more than one application this can soon become
> > tedious.  So, if you want to set up the remote machine as a SOCKS
> > proxy so that any socks-ified applications on the local machine can
> >
> > connect to the remote SOCKS, then you can use:
> >   ssh -N -D XXXX user@machine1
> >
> > For applications that do not have built in proxy capability you can
> > use e.g. proxychains.
> >
> > HTH.
>
> H'lo Mick and Carnek,
>
> The mention of XX and YY wasn't transparent, but a bit of
> experimentation gave a good connection.  Using the terms in my original
> post, I now have the following working command:
>
>    ssh -2 -N -L PORT:MACHINE.DOMAIN.COM:22 userid@IP_Address
>
> Just need to add an appropriate TCPKeepAlive and all will be good.
>
> Thank you both for your tips..

You're welcome.  BTW, port 22 in your example above does not *have* to be port 
22.  As a matter of fact if it isn't, it would avoid zillions of connection 
attempts by stupid botnets that could drive up your bandwidth consumption. It 
could also be the same port as the one you use at your local host. Whichever 
port you choose, you'll have to allow it through the firewall at the remote 
machine and of course whichever application is running at the remote host that 
you want to connect to, should be listening on said port.
-- 
Regards,
Mick