I am using an older version of sendmail that did not already have /etc/mail/relay-domains or /etc/mail/access. I had to create both files myself. I first created /etc/mail/access and it did nothing. (probably because I did not rebuild the database, since there was no database there in the first place) I then created relay-domains and deleted access. This worked perfectly for my local network, but not external.
After some tweaking and rebooting of my works server, I finally was able to get my home computers to use it as an outgoing mail server. (I think) I have not fully tested it yet. Apparently it only works if you put the EXACT IP address in. Not just a partial IP for the external network.
Lastly, my mailertable file has nothing configurable in it. Here's what that looks like, let me know if you see something configurable:::
# Copyright (c) 1998, 1999 Sendmail, Inc. and its suppliers.
# All rights reserved.
# Copyright (c) 1983 Eric P. Allman. All rights reserved.
# Copyright (c) 1988, 1993
# The Regents of the University of California. All rights reserved.
# By using this file, you agree to the terms and conditions set
# forth in the LICENSE file which can be found at the top level of
# the sendmail distribution.
VERSIONID(`$Id: mailertable.m4,v 8.18 1999/07/22 17:55:35 gshapiro Exp $')
# Mailer table (overriding domains)
Kmailertable ifelse(defn(`_ARG_'), `',