I installed SBS 2003 into an existing 2003 AD forrest using this method:
The only difference is I left both servers as global catalog servers so that I could migrate Exchange later.
According to that document, "If you already have Microsoft Exchange Server installed in the organization, the integrated Setup installs Exchange Server into the existing organization." ... which it did, and exchange still works fine ... I can receive email from the Internet, I can pull email over the Internet from my cell phone ... I use Web Access ... no problems at all ... EXCEPT .... mail will NOT go out. I cannot send from outlook, I cannot send from Web Access ... and I did notice a funky SBS 2003 SMTP connecter installed into the site, but initial inspection indicates to me that it's fairly harmless.
I tried stopping all exchange and smtp services on the SBS 2003 server, but that didn't fix it.
I cannot find any mail in the smtp folder que's, and so far, I am not receiving any bounce messages from the server.
I did tell the existing Exchange server to use the SBS 2003 server as its primary DNS server, but both servers are hosting DNS. I did manually test a port 25 connection from both Exchange servers to a server out on the Internet, and I was able to establish a connection from both boxes using a DNS name, so I know DNS resolution is working. I also did an NSLOOKUP and tested an MX lookup from each server, and resolution worked without any issues at all.
Does anyone have any idea what might be causing this problem?