This school system runs a shell called "AtEase" which basically prevents
student access into Mac system stuff. When doing admin work this shell is a
mild pain which is easily bypassed by starting up with the shift key held
down to skip loading system extensions. I was using this shortcut as I
installed and configured MacTCP, Netscape, etc.
Well, duh, MacTCP is also a system extension, so if you bypass extensions
on a restart it doesn't load -- no TCP, no IP socket. Our MacTCP config was
all correct, just as I thought -- the solution was to simply remove index
finger from shift key on startup, then all worked fine.
Thanks for all the feedback. Told y'all I knew just enough about Macs to be
dangerous, added a little more today. :-)