Question : Setup PTR record for mailserver

This system is on DSL behind an ordinary router.  The router has a static address and the servers and workstations use NAT addresses 192.168...   The router forwards port 25 to the Windows 2000 mailserver for SMTP and 53 for DNS. The server is Windows 2000 with Exchange 2000. I am using Microsoft's Windows 2000 DNS server in a basic configuration to facilitate internal name resolution; it relays DNS requests up the line for external DNS addresses.  The domain name is registered with Network Solutions but they forward requests to a DNS server managed by a company that runs our web site.  Everything is and has been working well.  

One of our outgoing emails was returned for lack of a PTR record.  I've tried to setup a Reverse Lookup Zone using alternately either the mailserver's NAT address or the router's WAN address.  When I check reverse lookup at www.dnsstuff.com I'm notified there is no PTR record. Is it possible to setup a PTR record given these circumstances?  If so, why isn't mine working?

Answer : Setup PTR record for mailserver

Your ISP needs to setup the PTR record. I am surprised that you don't have one already, even if it was host1.1.isp.com or something like that. Call the ISP and get them to put a PTR on the IP address of your mailserver and then wait. It can take up 48 hours before the rest of the Internet can see changes like this.

Simon.