Installing new sendmail version(s)

[Chris Torek]

In article <1915 at brl-smoke.ARPA> bgrm at MITRE-BEDFORD.arpa (Barbara Graham)
writes:
>... I want to install [a] new version [of sendmail], but since I have
>a sendmail daemon running, I can't just move the new sendmail into place.

Use `install -s -m 6755 -o root -g kmem sendmail /usr/lib/sendmail'.
This installs sendmail in /usr/lib, strips it, and sets its mode
to 6755 (rwsr-sr-x, setuid root, setgid kmem).  The group kmem
stuff is perhaps 4.3 specific: for security, access to /dev/kmem
should be restricted.  The easiest way to do this is to make
/dev/kmem mode 640, owned by root, group `kmem', and make any
program that wishes to read /dev/kmem setgid to group kmem.
(/dev/mem and /dev/drum should be similarly protected; /dev/kUmem
is purely for Unibus hacking and should be even more restricted.)

Once sendmail is installed, be sure to replace the frozen configuration
file, if you use one.  Sendmail is supposed to be smart enough to
ignore a frozen configuration for a different version of itself,
but this has had a history of failing, and a quick `cp /dev/null
/usr/lib/sendmail.fc; /usr/lib/sendmail -bz' will not hurt.

>It seems that if I kill the daemon, I'll hang the socket, so a new
>sendmail daemon won't be able to create the (already existing) socket.

This should not happen: killing the old daemon should free up the
socket.  Sendmail does *not* set SO_REUSEADDR, however, and in some
(many?) kernels there is a bug that leaves old TCP sockets around
on occasion.  Sendmail should not have to set SO_REUSEADDR; but if
you are not into ripping up kernel TCP code, you might try having it
do so.

>Has anybody out there managed to install a new version of sendmail without
>rebooting?

We do it every night.  It works fine, modulo the TCP bug (we keep
squashing it and it keeps returning in a different form with the
next TCP hack).
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 1516)
UUCP:	seismo!umcp-cs!chris
CSNet:	chris at umcp-cs		ARPA:	chris at mimsy.umd.edu