I frequently setup Exchange servers for businesses so I am quite familiar with the necessary steps required to do it properly. One thing on an mail administrators setup check list is DNS. Without the proper DNS entries, no one will find your mail server and you won’t be able to send mail reliably. That being said, it is imperative that you have a proper reverse DNS setup in place. Without going to deep into the actual details, rDNS requires an A record pointing to your mail server’s IP, and a PTR record that resolves your mail server’s IP to the name of your A record. This ensures that any mail sent by your server can be resolved using rDNS to validate you as the source. Most servers reject mail from servers that do not have valid rDNS configurations, primarily as defense against spammers.
For this particular client I already had the A record(s) created for me by their web host. Needing to get my PTR record created, I called into Embarq business support. As I expected, the person that answered the phone said, “I’ve never heard of reverse DNS or PTR records. Are you sure that you don’t need something else, I don’t think those exist.” Thats Embarq’s award winning technical support at work. I simply asked for an upper level guy and they transfered me. Imagine my surprise when they explained that they no longer setup PTR/rDNS for customers unless they have a T1 line. I was a little surprised because this was obviously not the case some 6 months ago. Fortunately for my client, Embarq is allowing DSL customers with mail servers to use Embarq as a smarthost.
To get your account setup for smarthosting, just give Embarq support a call and ask to speak with an upper level technician, they will help you create your username and password.
If you would like more information about rDNS, that can be found here. If you need to configure your Exchange server to use smarthosting and don’t know where to start, you can follow my howto here.