[lug] funky portforwarding ssh tunneling problem

[Hugh Brown]

I have an old legacy mainframe that only accepts telnet connections.  I
want to secure as much of the traffic to it as I can.  So, I am putting a
linux box next to it (on the same subnet) and I am setting up an ssh tunnel
to the linux box.  I want to use the linux box to forward that port to the
mainframe.

client<----ssh tunnel----->linuxserver<---portforward--->mainframe

I want to be on the client and type `telnet localhost 5000` and have it
make it to the mainframe with the data encrypted most of the way.

on client I have done this:

ssh -L 5000:localhost:23 linuxserver

on the linux server I tried allowing access on the telnet port and doing
this

ipmasqadm portfw -a -P tcp -L linuxserver 23 -R mainframe 23

but I am having no luck with the linuxserver to mainframe jump.

I am not dead set on using ipchains and ipmasqadm but I do need to be able
to encrypt the traffic from client to linuxserver and to be able to 

client% telnet localhost 5000 

and get exactly the same thing as if I had done:

client% telnet mainframe


Any ideas?

Hugh