We have encountered an issue with publishing Exchange 2003 OWA on a ISA 2006 using kerberos constrained delegation. The issue is, that when we authenticate to ISA successfully we are again prompted for a password on the OWA page. Kerberos delegation works correctly, I assume this because we created a virtual directory on the same IIS site where OWA is located. The site displays correctly without prompting for a password after authenticating to ISA. The OS is Windows Server 2003 Std with AD and Forest at a 2003 Functional level. This is a test setup where everything is located on the same machine (Domain controller, ISA 2006 and Exchange). Could this present a part of the problem? When we traced the IIS, we received the following events:IISAuthentication, AUTH_START, 0x00001530, 128292434126718750, 45, 0, {00000000-0000-0000-2500-0060000000fc}, "NT", 0, 0IISAuthentication, AUTH_REQUEST_AUTH_TYPE, 0x00001530, 128292434126718750, 45, 0,{00000000-0000-0000-2500-0060000000fc}, "NT", 0, 0IISAuthentication, AUTH_SUCCEEDED, 0x00001530, 128292434126718750, 45, 0, {00000000-0000-0000-2500-0060000000fc}, "NT", FALSE, "EXCH\statuser", "EXCH\statuser", 0x00000002, 0, 0IISAuthentication, AUTH_END, 0x00001530, 128292434126718750, 45, 0, {00000000-0000-0000-2500-0060000000fc}, 0, 0I believe this shows Authentication is successful using Kerberos, this is repeated twice, until the following is encountered: IISAuthentication, AUTH_START, 0x0000089C, 128292434129531250, 90, 30, {00000000-0000-0000-2b00-0060000000fb}, "NT", 0, 0IISAuthentication, AUTH_REQUEST_AUTH_TYPE, 0x0000089C, 128292434129531250, 90, 30, {00000000-0000-0000-2b00-0060000000fb}, "Anonymous", 0, 0IISAuthentication, AUTH_TYPE_NOT_SUPPORTED, 0x0000089C, 128292434129531250, 90, 30, {00000000-0000-0000-2b00-0060000000fb}, 0, 0IISAuthentication, AUTH_END, 0x0000089C, 128292434129531250, 90, 30, {00000000-0000-0000-2b00-0060000000fb}, 0, 0 IISCache, HTTPSYS_CACHEABLE, 0x0000089C, 128292434129531250, 90, 30, {00000000-0000-0000-2b00-0060000000fb}, FALSE, "HTTP_STATUS_NOT_OK", 0, 0The second IIS authentication occurs twice and subsequently fails if we don't enter credentials, the IIS error is 401.2 error, and we are presented with the following Error: Access is denied on the OWA page. Does the second error indicate, that it is attempting to use the anonymous user account to access a resource which it does not have permission for? regards, Simon