Pigeon wrote:
...this kind of brings me back to what I guess was a point somewhat obscured by my rambling... How does one retrieve the *definitive* information as to whether an IP is static or dynamic?
Reverse DNS gives a lot more credibility to your domain as it requires the intentional participation of the netblock owner (or the ISP the IP is allocated to). If you still have the default xxx.xxx.adsl.myisp.com reverse in there, that says to the world you're no different then the infected Windows user down the street. Go through the effort to legitimize your server and you'll get your mail through. In most circumstances an ISP won't give you a reverse DNS on a dynamic IP.
-eric