Question : Creating Record for 1st AD server with DNS in Server 2003

Hello... Another expert helped me get my AD server off the ground and showed me how to configure zones. This is something I've had a very hard time getting my head around.
Although I know it will benefit me, the reason I implemented a DC was to teach myself the technology.
 I'm told that the DC is to control the resources available to local clients only but every time I point certain server's NIC cards DNS to the DC I get weird results and I think it is in my records. For instance my web server, "Terminal-server" [10.1.3.40], also hosts a 3rd party mail server. When I point the DNS to DC, "Domain-1" [10.1.3.250], I get error in mail log:
.................................

10.1.3.250      [000002B4] Fri, 16 Oct 2009 20:54:43 -0400 >>> 250 mail1.electriciansnet.com Hello domain-1.NLPCG.local [10.1.3.250], pleased to meet you.
10.1.3.250      [000002B4] Fri, 16 Oct 2009 20:54:43 -0400 <<< MAIL
10.1.3.250      [000002B4] Fri, 16 Oct 2009 20:54:43 -0400 >>> 501 5.5.4 Syntax error in parameters scanning
................................

And mail stops working.

Also, no matter how I set permissions in IIS on this server, I eiteher get an authentication login screen or a "You are not authorized to view this page" page.
Finall, my host header has stopped working.

I have included a map of the domain.

Note: no-ip.com hosts my public domains and I use mail reflector which points right back to 25 because my emails do  not reachtheir destinations otherwise but I think I need an MX to mail1.no-ip.com priority 5

Can someone please help me out and explain as we go so that I can try to get a better handle on it?
mail2.no-ip.com priority 10

Answer : Creating Record for 1st AD server with DNS in Server 2003

I don't need any special records at all right?
Nope, all the special DNS records are created by domain controller

Should I make local A records for mail www ftp servers?
Nope, you don't need to do that locally, it is already done on your external name servers

Should I make any MX record?
Not internally, and looks like it is set properly externally since you can fetch your emails

Should I use server or scope options?
Which options? ftp? www? pop3? smtp? router?
For DHCP, Scope options is sufficient to start your 1st domain, you will need Router, DNS, DNS Domain Name, WINS (If you have it), the rest are optional according to what you will be planning on your network.

Should name server be set to DC?
100% Yes, for domain computers to function properly they will need to have the DC as the DNS server, but make sure the forwarders (or root hints) are set up properly so that your computers can resolve outside addresses as well.

Anything else?
Yes, take the administration account out of IIS, it is as if you're giving everyone on the internet admin access to your web server. Try creating a limited account and set it up instead of the administrator user