HELP! I can't NFS Mount Ultrix 4.1 disk from SunOS 4.1.1! Aarg!

[Steve Lincoln]

I have a funky brand-spankin'-new Sun SPARCStation 2 which was shipped
with SunOS 4.1.1 pre-installed.  On this machine, I cannot mount disks
which are on a DECStation 3100 running Ultrix/UWS 4.1.  

Relevant facts:

* The Sun is a YP client of the DECStation YP Master Server.  
* Other networking stuff seems to work fine (rlogin, etc).
* The DECStation CAN mount disks from the SPARC-2! Just not vice-vera.
* A SPARC-1 running 4.0.3 can mount disks from the DECStation.
* Other DECStation YP Clients of the DECStation srever can mount its disks.
* The message I get is:

server not responding: RPC: Authentication error; why = Invalid client 
credential

Yes, the SPARC2 is listed in the DECStation's /etc/exports file.  Can
anybody help?  Naturally, I will post the fix.  Thanks!

Steve Lincoln  (lincoln at genome.wi.edu)
MIT Center for Genome Research
Whitehead Institute for Biomedical Research