Reverse DNS and RFC 2317

[Don Stokes]

Len Conrad  <lconrad at go2france.com> wrote:
>More and more mail servers are performing these kinds of DNS validations, 
>so the reverse delegation and PTR records of at least a mail server are 
>increasingly important for reliable mail delivery.

You don't need the reverse maps *delegated*, you just need them to be
there.  It's fine if the ISP provides their own names, eg 
ip-99-88-77-66.isp.net for 66.77.88.99.in-addr.arpa, as long as both
forward and reverse maps are present and consistent. 

An ISP that doesn't do *something* with its reverse maps is
demonstrating insufficient clue to be an ISP, IMAO.

-- don