Installed Windows 2003 Server, then Exchange Server 2003 - No problem installing, but I had a hell of a time getting the email to work. I could send email, but not receive any. Here is what worked for me...

Make sure you have a recipient policy for the domain you're trying to send mail on. Without it, your server thinks it's relaying for foreign domains. You have tell exchange what your domain name (theblattners.com in my case) is. Here's how...

1. Goto your Exchange administrator MMC (System Manager)
2. Select Recipients -> Recipients policies
3. Right click 'Default Policy' in the right window and click 'Properties'
4. Click on the 'E-Mail Address (Policy)' tab
5. Click 'New' and then 'SMTP Address' then 'OK'
6. In the 'Address' box, type @ then your registered domain name (in my case @theblattners.com)
7. Now, click 'OK'
8. Select the SMTP entry you just added, and click 'Set as Primary'"
9. Now, just click 'OK' - Your should be able to get mail now.

Here is a great place to test your email connections http://www.zonedit.com/smtp.html

Here are some other posts I found whilt searching for a solution for my problem - maybe one of these would help...

1. Goto your Exchange administrator MMC.
2. Under your administrative group and %YourServerName% open the Protocols folder and under SMTP, goto the properties of your Default SMTP Virtual server.
3. Click on "Delievery" tab and then the "Advanced" button.
4. Under Fully-qualified domain name. Put in... "%YourServerName%.company.com"
5. Press OK and test.

Try this....open you System Manager...Click on servers...then your server...Then expand your Protocols, and click on your SMTP folder....right click on your Default SMTP Virtual Server and go to properties...Click on the Access Tab and then relay and make sure that your "Allow all computers that successfully authenticate to relay, reguardless of the list above.

Make sure to set up you clients' Outlook and Outlook Express accounts correctly. I had another problem with a machine not sending email. The user (my beautiful wife) never logs in under the domain name, she always logs in to 'This Computer'. Well, Exchange Server requires SMTP Authentication. Here's how to set that up in your Outlook clients...

Here is a portion of the error message you will receive when trying to send using Outlook Express

So, if you are getting an SMTP error please check that the "my server requires authentication" box is checked in your mail settings.

Enabling SMTP Authentication Within Your Mail Client
1. Click Tools
2. Click E-Mail Options
3. Click View or Change Existing E-Mail Accounts
4. Highlight your account
5. Click Change
6. Click More Settings
7. Click the Outgoing Server tab
8. Check the box My outgoing server (SMTP) requires authentication
9. Click Apply