[vdubjunkie]

j65nko, no need to shut up. I appreciate the help. You have always been very helpful and knowledgeable. At this point I'm not wanting to implement ssl, but as it turns out, what I'm wanting to accomplish is very doable by simply understanding the postconf a bit better. For anybody who might be thinking they want what I was describing, here is what I learned:

mydestination = $myhostname, localhost.$mydomain, localhost
relay_domains = $mydestination
mynetworks = 10.x.x.0/24, 172.x.x.0/24

The domains referenced in "mydestination" are allowed as domains which this server will "relay for" and therefore allow anybody who connects to submit mail for that domain. The "mynetworks" is automatically allowed to relay to any domain. This is exactly what I was looking for. If I wanted to, I could add a block of IPs belonging to my phone network in "mynetworks" so that I can send email from my phone.

Thanks again for your willingness to help j65nko. You are one of the integral reasons this forum (now and it's first incarnation) is one of the very best. BSD is only as good to new people as the people supporting it.