Question : Setting up exchange

Ok, so here are all the particulars.  I have a Server 2003 Standard.  We decided to host mail internally to use the advantage of exchange.  I installed 2003 Exchange sp2.  Now for some reason or another I can not get mail to the server.  Here are a few of the issues.

The email domain is mydomain.org , the local domain is domain2.org.  Cbeyond the phone, interent, and previous e-mail provider does the DNS for mydomain.org.  They can only change the MX record to a name.

I bought the domain2.org domain name from godaddy, to try to fix things up I have not been able to get it to the server.

THere is no firewall except for the cbeyond modem.  

Cbeyond told me I had to redo my local domain.  That can't possibly be the best way.  How can I get mydomain.org email into exchange.

Answer : Setting up exchange

Have you pointed the MX record to your fixed IP address and opened up port 25 on your modem / router and forwarded it to your server?