Not sure if there is anyone with enough knowledge to help me out here.

I need a little help on DNS.

I have a friend who wants to setup an Exchange Server, his Broadband connection has static IP addresses. I have loads of experience in MS Exchange and quite a bit on Internal DNS servers, but this guy was harping on about getting the ISP to set a reverse DNS entry to ensure they do not get marked as spam.

I have worked with Exchange for many years and have my outbound emails going through an SMTP connector and have never had any problems despite not having a reverse DNS record setup on my ISP.

My question is, why would this guy want a reverse DNS entry, why have i never had a single problem in the past without one?

I assume it is because i have an SMTP connector setup routing all my emails through a relay, and he is thinking of setting exchange up without this?

Why doesnt the guy buy him self a Domain name and use that ? Or use a Free reverse DNS im supposing the guy wants to point a name to the Exchange server i have no experience with Microsoft Exchange so i cant really help there.. But if the guy does want that then he should look into it more otherwise obviously to get to the server its just the ip address.. Or another option rent a co-location server.. But like i said i have no exeperience with Microsoft Exchange so i cant be of much help.. Lets hope some others have any ideas

Doesn't matter, i have sorted it.

For reference, ISP stopped relaying emails several years ago due to being used as open relays to send spam from compromised PC's. So when Exchange sends emails by connecting directly via DNS, on mail systems that require a reverse DNS there is no record on the internet of the IP address relating to the domain name hence why some email systems will reject the email. So having the ISP setup a reverse DNS record it relates the static IP address to the domain name which is acceptable.

The reason why my email has always worked without reverse DNS setup is because my email is sent through a smarthost which has the reverse DNS setup as part of the package.

Simple really.