Attempts to run usernet on a remote client fail. Apparently it is not respecting the -display option that all X applications are assumed to support. I have two machines networked together, only one of which has a modem and is configured to set up a ppp connection to a remote ISP. IP Forwarding is currently disabled. Users on the second machine use rsh to run internet applications on the first machine. Works fine with everything except usernet.
you can use DISPLAY=foo.example.com:0 usernet to run it.
Could not replicate this problem on a test lab machine.