A secure connection to an SCO Unix 5.2 behind a pf firewall.

[eculp at bafirst.com]

I installed a FreeBSD6.0 server/firewall for a remote customer about a 
week ago.  Today they told me that on there LAN they had a Unix box 
that runs their internal ascii based accounting system that they have 
been accessing by modem from home.  Now they want to access it over the 
Internet.  The box is a pentiumIII running a SCO unixV from 1990 or 
2000 with no secure anything that I have been able to find.  In fact 
the company who maintains their system uses uucp for updating.  I was 
thinking ipsec, originally but now I don't see a way to configure the 
SCO end of a tunnel.  The server has a simple pf firewall with only a 
few ports open and opening ports isn't a problem.  The application is a 
terminal session.  Thirty users login in to it as root all with windows 
terminal sessions except for the modem connections and to make it more 
fun I shouldn't modify the SCO box because of their service contract.

I would appreciate any suggestions for a reasonably secure solution.  I 
just found all this out and am totally blank.

thanks,

ed