Problems with Yellow Pages (ypserv ?)

[rc at wyse.wyse.com]

We have a strange problem with yellow pages running on a network of
Sun 3's (3/280, and lots of 3/60). Apparantly, something is not
mapping login id's to uids properly. From a yp client, typing 
the command "ps -aux" generates output lines (apart from other standard
daemons) with user "(null)" as follows ...

USER       PID %CPU %MEM   SZ  RSS TT STAT  TIME COMMAND
(null)    7364 70.6  1.0  360  320 p4 R     0:02 ps -ux-a
(null)     219  0.0  0.3  200   80 p0 I     0:01 -csh (csh)
(null)    5063  0.0  0.6  272  192 p5 I     0:02 -tcsh (tcsh)
(null)    2117  0.0  0.4  216   96 p7 I     0:01 -csh (csh)
(null)    7300  0.0  0.8  272  248 p8 S     0:02 rn
(null)    7285  0.0  0.3  200   80 p8 I     0:00 -csh (csh)
(null)     777  0.0  4.9 2016 1560 p1 S     0:18 emacs
(null)    5736  0.0  0.7  216  200 p7 I     0:00 Mail
(null)    1806  0.0  0.4  216   96 p3 I     0:01 -csh (csh)
(null)     277  0.0  0.4  232  112 p2 I     0:13 -csh (csh)
(null)     767  0.0  0.3  208   88 p1 I     0:02 -csh (csh)
(null)    3796  0.0  0.3  200   80 p9 I     0:01 -csh (csh)
(null)    3667  0.0  0.3  208   88 pc I     0:00 -csh (csh)
(null)    6241  0.0  0.6  272  192 p4 S     0:05 -tcsh (tcsh)

This is not really causing any *major* inconvenience at this 
stage but is kind of annoying. The strange thing is that it
allows a person to login to a remote workstation running YP.

Commands like "w" and "who" work fine - i.e. it does produce the
correct login name - uid mapping. However doing a "finger user"
or "finger user at ypmaster" (where ypmaster is the YP Master machine)
or "ps -ux" just freaks out.

Any ideas as to what might be wrong or what kind of a workaround
solution might be available ? We are running 3.5 and 3.5.1

Thanks in advance.

Ran-Chi Huang
Wyse Technology                 VOICE: (408) 433-1000 x1537
3571, N. First Street           ARPA:  rc at wyse.com  OR  rc at caf.mit.edu
San Jose, CA 95134              UUCP:  ...!{uunet}!wyse!rc