help - 4.0.3 troubles

[P. Glassenbury]

We have a sun3/60 server and a sparcstation server with some sun3's and
another sparcstation as clients off the sparcstation. They are all running
SunOS 4.0.3 . We got an official B class ip number and have recently
changed to it with a netmask of 255.255.0.0

The sparcstation and one 3/50 client works fine, but the other sun3
clients all hang going into multi user mode. They all work in single user
mode.  They all appear to have the same files in their root space.
Rpc.statd and rpc.lockd both die, saying they can't register their
services.  Then we get "NFS server not responding" messages, even though
the NFS discs mount fine(by hand on the clients).  Also ypbind and portmap
are both running.  

Any ideas about the solution, or even about how to better define the
problem :-), would be welcome.

Also, we have our mail directory on one server with all the suns sending,
or using NFS, to append mail to that mailbox.  Sometimes we get bounced
messages saying:

	--------Transcript of session follows ------
	mail: /var/spool/mail/pete: cannot append
	mail: cannot open dead.letter
	554 pete... Service unavailable

If the mail box file exists or someone mails from the server to that
person all is ok. If someone mails to the person from a client or off-site
and that mail box doesn't exist it gets thrown away and the headers sent
to postmaster (me). I know that "set keep" in .mailrc keeps from being
deleted. We have had sendmail creating the mailbox if it didn't exist
(under current SunOS) but now it doesn't go.  Any ideas?? Is it connected
to YP and/or NFS troubles above Please mail to me (soon :-) ) and I will
summarise if there is interest