I have built a DNS/DC/Exchange server to handle mail and clients for a small domain. Previously, I was using HostPC to host my webpage and mail server. What I wanted to do, was leave the web page hosted there, but deliver mail to my domain to the new Exchange server at my house. However, HostPC gave me no way to point the primary MX record to anything other than their domain. By using ZoneEdit, I was able to get them to provide the nameserver, and I had a lot more options on my MX records. I now successfully have my domain's mail delivering to my home mail server, which technically is a dynamic IP. Just in case my IP changes, I have a dynamic DNS through yi.org The only problem I have now, is that by default, the Exchange server uses it's own domain to send mail by default. When I try to send e-mail to most addresses, I'll get a rejection message mentioning either "open relay" or "dynamic IP". I've ran several tests to ensure I'm not running a mail server spammers can relay through, so it has to be because my IP is dynamic. Now realistically, my IP never changes. I've lived at the same place for almost a year now, and have only had two IP addresses. Even that was only because my dog chewed through the cable line while I was away, and the connection was down for over 3 days, allowing my DHCP lease to expire. I've added the POP account in all my Outlook clients to check the server from HostPC (set as secondary in the MX record) just in case mail is not delivered to my home server. I have also set it as the "default" account, hoping outgoing mail would always send through there. However, it doesn't always. I usually have to change from "Microsoft Exhchange Server" to mail.mydomain.com set up at HostPC. I see two solutions to this problem: 1) Somehow force the Outlook clients to send e-mail using the POP server at HostPC only, OR 2) Force the Exchange server to route outgoing mail through the HostPC servers, so I don't get the rejection message. I've tried adding mail.mydomain.com to the "Smart Host" box under Virtual SMTP server, but that didn't seem to do anything. Any ideas??

The recommended solution here would be to see if your ISP will allow you to use their SMTP server as a smarthost. "If that [soiled bed] sheet is a [holy] manifestation, then I'm working on a miracle in my Jockey's!"