Reverse DNS (I think..)

The issue is this, I have a mailingscript which sends mail to a number of persons every now and then. When I check the mainlog some providers decline the mail because the sender is an IP address. My users pages too are findable through IP/~user. Now I suppose I'll have this issue fixed, once users are reachable through DOMAINNAME/~user. Domainname being the domainname of my server of course.

How should I manage my DNS settings to enable this? And will this fix the mail-issue (sendaddress and replyaddress are filled in)?

You're right in that you need reverse DNS for your server's main IP#.

Most providers don't delegate reverse DNS authority to their clients so you'll probably need to get your connectivity provider to set up your reverse DNS for you.

Your main IP# should have reverse DNS to the server hostname.

Jeff