Home Network :: Virtual Servers On One IP Address

I have one dedicated IP issued to my home, along with another dynamic one if I need it(but I don't use it). I have a webserver, mail server, and name server up and running on a single machine exposed to the internet with my static IP. I have a domain name registered to my IP address. My webserver and name server work great, but I am having difficulty with the mail server. In order to have mail work correctly, I have been told that I need to get reverse DNS setup for my domain (something I had neglected to do). My nameserver responds to reverse lookups correctly when issued locally, but it looks like queries from the internet never reach it (I think my ISP catches requests upstream). I contacted them and they put a PTR record in for my IP pointing to ns1.mydomain.com. This all works fine, but the thought occurred to me that if in my hosts file I put my MX record in as mail.mydomain.com., any mail clients that do a reverse lookup of my IP won't get mail.