NFS mounted /usr/spool/mail under SunOS 4.1

[ramey at jello.csc.ti.com]

I recently installed SunOS 4.1 on a Sun 4, and imported that system's
/usr/spool/mail directory from a Sun 4 running 4.0.3.  I noticed a couple
of things: it seems that sendmail notices that /usr/spool/mail is mounted
on a NFS directory, and mostly ignores the sendmail.cf file if this is the
case.  It seems to just blindly forward any outgoing mail to the NFS
server.  Is this documented anywhere?  I read the release notes, and
skimmed through the sendmail docs, but couldn't find any mention of this.

Also, I couldn't get /usr/ucb/mail to work properly in this case.  It
takes several seconds to start up, prints out the subjects, then exits
when you try to read a message.  /usr/bin/mail works okay, as does
movemail (in GNU Emacs rmail).  I also compiled up Mail from the 4.3 bsd
tahoe sources, and it works fine too.  I guess it has something to do with
locking, but I couldn't tell exactly.  I don't allow root access to this
filesystem (in the server's exports file), in case this matters.

Has anyone else had similar experiences?  Does the fact that the server is
running 4.0.3 instead of 4.1 make any difference?

Joe Ramey
TI Computer Science Center
ramey at csc.ti.com