Setting up reverse DNS correctly

[Craig L. Ching]

"Justin Randall" <j_randall_ at hotmail.com> wrote in message news:<cd4tu0$26e2$1 at sf1.isc.org>...
> There are two solutions in this case, the one that is least likely to be the 
> actual solution would be to ask your ISP to delegate a portion of the 
> reverse records (PTR RRs) over to your name servers.  There is a CNAME hack 
> that can easily accomplish this.
> 
> The most common and more likely solution is to contact you ISP and request a 
> reverse entry be made in their records to the effect that a query against 
> your IP will resolve your mail server FQDN.
> 
When you say my ISP, you mean the people who assigned the IP address
to me, is that correct?  And even though I run my own name servers,
they have to do something on their end to make it work?

I'm afraid to say I've never taken the time to really understand DNS
details, it mostly just works for me.  Could someone elaborate on how
the ISP fits into this scene?  Does it have something to do with the
root servers knowing which ISPs own what blocks of IP addresses?  I
always thought that once I gave my name servers to a registrar, the
root servers contacted my server directly about my domain names. 
Sorry for such a novice question, feel free to direct me elsewhere if
you think it's necessary.  And thanks for the help!

Cheers,
Craig