SUMMARY (Preliminary): Shared Mail spool compatibility between Suns and SGI

From: Bill Hart (
Date: Fri Jun 05 1992 - 08:37:52 CDT

My original posting :-
> Hi,
> A couple of months ago I tried to centralize our mail accounts onto one
> server, a Silicon Graphics 220S running Irix 4.0.3, with a whole bunch of Sun's
> (Sparc stations running 4.1.1 and 4.1.2) mounting the mail spool directory.
> We also have PC's running PCNFS 3.5c and Lifeline mail, and Macs using cap60 and
> Eudora. Things are now a bit of a mess, and my users are losing confidence in
> the mail system. The problems are mainly between the SGI and the sun's, the SGI
> likes to create mail files with permisions 660 and group mail (tty on Suns),
> the suns like to create the mail files 600 and owned by the users normal
> group. I've tried fiddling with suid and sgid permissions on /usr/bin/mail and
> /usr/ucb/Mail on the suns, but which is ok so long as people don't empty their
> mail files and the mailer has to create a new one. When this happens, unless
> I fix up the permissions, mail starts bouncing all over the place.
> So has anybody out there done this and got it to work ? or have any suggestions ?
> Or would I be better of forgetting about it ?

Well I got quite a few replies and some useful advice on this one. The simplest
solution is to get a publically available binmail and modify it to make sure that
it will create files with the right permisions. An alternative is to put "set keep"
in the system /usr/lib/Mailrc so mail doesn't delete the users mail files when
they are empty.

However evidently this will not solve all mail problems. Supposedly nfs mounting
mail spool directories is **not** a good idea, especially between machines with
different versions of unix, because of the unreliability of file locking some mail
is bound to get lost through different mailers trying to write to the same file at
the same time. The standard solution is to create a central mail hub and modify
all the sendmail files on the other machines so that mail delivery is only done
on the mail hub and get rid of all the nfs mounts of mail spool directories.

One thing I don't like about this is that then users can't read and post mail on
their local machines, except by running remote shells and the like, and they can't
use their Sun mailtools. There are a couple of possible solutions to this one
is to get the Rand MH system working and use xmh instead, another is to use
POP as the standard mail protocol and have pop clients on all machines. I've
been given a version of mail which uses pop and am in the process of trying to
get the Rand POP server working (it seems to be the only one that uses the
RPOP command) and will see if mailtool can be made to coexist with the new pop

I should stress that I have been warned that even nfs mounting the mail directories
only between sun hosts is likely to cause mail to occassionally get lost because
of the unreliablility of the lock daemon.

So to summarize what I plan to do is :-
        1) Get the rand POP server working and the pop version of mail working
        2) Try to get the pop version of mail to coexist with mailtool
        3) reconfigure sendmail so that local mail delivery is only done on the
mail hub
        4) disconnect the nfs mounts.

I'm only at stage 1 so far, so I'll post a final summary when I get it all working
(if possible).

Thanks to :-

Any further comments also welcome,

Thanks again

Bill Hart Internet :
Network Manager Phone : +61 02 206 442
CSIRO Division of Oceanography Fax : +61 02 240 530
Hobart, Tas., 7000 Australia Paging: +61 08 001 234 (quote #29474)

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