How to enable Anonymous Access in IIS 6

What are the account requirements for aspx pages to be accessed anonymously on Windows 2003 server?.

When I view my aspx page in a browser locally or remotely I always get prompted for user and password. When I provide credentials for user in the admin group the page displays correctly.

I do not get prompted when viewing .htm files.

I would like to make the aspx pages available anonymously.

Here are my settings:

NTFS Directory Security:
Administrators - Full Control
ASP.NET Machine Account - Read & Execute, List, Read
Internet Guest Account - Read & Execute, List, Read
System - Full Control

Virtual Directory Tab:
Read - checked
Execute permissions - Scripts only

Authentication and access control:
Enable anonymous access - checked
User name: IUSR_COMPUTER_NAME
Basic Authentication - Not checked

Thank you in advance.

Not sure, but you need to make sure that the Internet Guest Account can read the file needed for ASPX pages, which is probably located here:

C:\Windows\Microsoft.NET\Framework\v1.1.4322\aspnet_isapi.dll

(that may be different depending on your version etc.)

Thank you, EdwinBrains.
You are right, giving the Internet Guest Account read rights to the aspnet_isapi.dll file resolved the problem.

Questions:

What group(s) should the Internet Guest Account be in? By default that account is only a member of the Guest group.

What users/groups should have access to the aspnet_isapi.dll file.
I checked other 2k3 boxes and the following users/groups are listed in the Security settings for the aspnet_isapi.dll file.
Administrators
ASP.NET Machine Account
IIS_WPG
Local Service
Network Service
Power Users
System
Users

I know that giving read rights to the IUSR_Machine_Name for the aspnet_isapi.dll file would solve the problem, however, I am trying to figure out the correct way the server should be setup.

I must have done something wrong to cause this in the first place as I don't hear anybody else complain about this.

Well I'm not entirely sure, but you want to give the least amount of permissions as possible to make it as secure as possible.

I don't think you want to add the Internet Guest Account to any other groups though, to reduce the chance of hackers breaking into your web server.

I think Doug G will give you more info about which groups should have access.

I don't ever add IUSR_whatever to any additional groups, but then again I only work on small systems.

I gave the anonymous account (IUSR_MachineName) read access to the abovementioned DLL but still didn't work.
The way I "solved" this problem was activating sub-authentication in IIS 6.0 (which poses a security threat), IIS 5.0 uses sub-authentication by default when you enable anonymous access but IIS 6.0 does not. For details on how to do this, please refer to http://support.microsoft.com/default.aspx?scid=kb;en-us;332167
Hope this can be of assistance, even though you solved your problem already.