[Cialug] RFC & best practices for mail server hostnames?

[L. V. Lammert]

I found out recently that a major insurance company (State Farm), has at
least two email servers that are not configured with hostnames - as a
result, our mail servers regularly block emails from statefarm.org.

Is RFC2821/3.6 the governing document? It's hard to tell the difference
between therein as to whether the *dns* hostname governs, and if there
is a different RFC referencing the hostname in the EHLO.

Any references would be appreciated, I think I am finally getting through
to some folks that handle their core servers.

	Lee