> I get no emails send to root from the daily or security secripts, or
> when cron fails a job.

For me, that install procedure with build.sh will not modify my
/etc/rc.d/sendmail and /etc/rc.d/smmsp scripts, so I had the same
problems until I copied those manually from /usr/src/etc/rc.d/ ...
Moreover, I had to do the same for /etc/defaults (since sendmail=YES
nowadays by default) (also check /usr/src/UPDATING file about the
issue)...

Then as I only wanted local mail delivery, I had to modify
/etc/sendmail.cf to only listen to 127.0.0.1 as opposed to 0.0.0.0
which seemed the default. Lame, but this is related to current
sendmail not just NetBSD.

To flush the /var/spool/clientmqueue mail I had to use smmsp=YES in
/etc/rc.conf and to do /etc/rc.d/smmsp start (then all old mail which
was queued and never could be delivered was processed). Now everything
works fine, except for the fact that I have sendmail MTA running
listening to 127.0.0.1 (which ideally would not be necessary, but is
now). So I have conflict with my own MTA I run which doesn't handle
local delivery (only virtual email accounts), which can no longer
listen on localhost. Not too much of a problem but still an
annoyance...

I also agree that the defaults should be for a running system with
sendmail only listening to localhost interface. This seemed broken
when I installed 2.0_BETA snapshot some time ago, not sure if it's
proper now, but updating userland using install=/ didn't update the
files in /etc or me so it was still broken...

Supposedly one can configure NetBSD to use postfix which would also
need to launch a few processes but which would use AF_LOCAL sockets
instead of TCP for local mail delivery, I couldn't test this setup yet
however.