Marrying Active Directory to ASP.Net

[N4JRY]

Hello,
Thank you for reading. I generally spend time with the C# forum but today have an admin issue...

I have a two virtual servers; SQL1, WEB1.
A web site on WEB1 is using Windows authentication. This appears to work correctly - querying the active directory on SQL1 (domain is Dev).
The issues:
1) If I log in to the web site using windows authentication as Dev\Administrator, it authenticates correctly but User.Identity.Name returns Web1\Administrator.
This seems strange to me.
2) Dev\RecosAdmin logs in (the web authentication succeeds) but cannot run the website resulting with the error:
"Some Or All Identity References Could Not Be Translated"
3) If I create a local user Web1\RecosAdmin I log in correctly and the site works perfectly.
4) If I add <identity impersonate="true" /> to the web.config I get a 500 - Internal Server Error

What is it I am missing? Is a trust needed somewhere or a security level for the app pool...? Scratching my head now. I would have posted this within an ASP.net formum but I believe it is a server admin issue. Please let me know if this is not the case.

Nicholas

[pjhutch]

Enable Anonymous login on the website and change the IUSR_ServerName to a Domain\Username account instead which the Impersonate setting will use.

[N4JRY]

Thank you for your response and sorry for my delay in replying.
We have had to put this one down for the momenent to continue the rest of the development.
We need the windows athentication so the Anonymous scenario is not viable. It is within a secured environment and people do not want to log into the system.
For authorisation we are currenly using SQL's but will be changing that shortly but it does require using the correct user name.
Why this does not work is a mystery.

Nicholas