After upgrading to Internet Explorer 6, Internet Explorer can NOT negotiate Kerberos authentication with a server that supports Kerberos, like IIS 5.0?
Internet Explorer 6 defaults to NTLM or Windows NT Challenge/Response.
To resolve this issue:
1. Close all but one instance of Internet Explorer.
2. In Internet Explorer 6, use Tools / Internet Options to select the Advanced tab.
3. Under Security, check the Enable Integrated Windows Authentication (requires restart) box and press OK.
4. Restart Internet Explorer.
You can also implement this feature using the registry:
1. Copy / Paste the following to a EnableNegotiate.reg file:
2. Merge the EnableNegotiate.reg file with the users registry.
NOTE: Older operating systems do NOT support the Enable Integrated Windows Authentication (requires restart) feature.