[lug] sendmail box as secondary mailserver for domain

[Andrew Diederich]

I'd like to setup a box running sendmail that's outside our firewall as a
secondary mailserver.  We currently don't have one which makes me . . .
nervous.  (I didn't design this network, I just inherited it.)  Whining
aside, I just can't figure out the dang /etc/sendmail.cf file.  (Oh, I'm
running SuSE 6.1.)  As close as I can figure it, I just need to add another
mx record to our dns at a higher preference level, and then in sendmail.cf
maybe add our domain in the list with the Cw.  Hmm, that sentence isn't
English.  Examples:
here's what our SOA record looks like in DNS:
$ORIGIN com.
NETdelivery     IN      SOA     castlepeak.NETdelivery.com.
andrew.NETdelivery.com. (
                97102103 43200 600 86400 3600 )
                IN      A       206.204.3.85
                IN      NS      NS1.NETdelivery.com.
                IN      NS      quandarypeak.NETdelivery.com.
                IN      MX      10 castlepeak.NETdelivery.com.

I know I'll need to add an "IN   MX   20 quandarypeak.netdelivery.com."
there.

sendmail.cf:
Is now: Cw localhost quandarypeak.netdelivery.com 
change to?: Cw localhost quandarypeak.netdelivery.com netdelivery.com

Is this how I turn my box into a secondary mail recpetical?  Or do I need to
do other magic in sendmail?  I've looked through the O'Reilly System Admin
and TCP/IP books, but didn't see what I needed.  Yup, I'm pretty needy this
week.

Andrew Diederich
andrew at netdelivery.com