Cognos server call to a DNS CNAME - Cannot login

[Nimirod]

Hi all,

First at all, thanks for any help you can provide.

I'm on a Cognos 10.2.1 FP2
windows Serveur 2008 r2  IIS 7.5

Our server is working perfect but we decided to create a DNS Alias to acces the server (CNAME cognos.mydomain.com for a serverfullyqualifiedname.mydomain.com)

When accesing our server from the fully qualified name it works but when accesing the CNAME alias we have the Cognos Prompt for credentials but the logon doesn't work it seems as it try to negociate access but fails and continue asking for password.

I've done this before and it always work without any specific configuration on Cognos side.

Some ideas ?

Thanks.

[sir_jeroen]

Nimirod,
I know this issue. I have this problem when using the cname on the server itself. (I simply turn to the original name).

Maybe this url helps: http://blogs.msdn.com/b/friis/archive/2009/12/31/things-to-check-when-kerberos-authentication-fails-using-iis-ie.aspx
Please let us know if it helped.

[Nimirod]

Thanks RN Addict for all thoses hints. I'll check ASAP and i'll come to you again soon.

[Nimirod]

Our problem came from an underscore in the cname ( mydomain_test.com/ibmcognos )

While Firefox can deal with, IE fails to pass credentials from an underscored call.
Thanks fiddler software to help me find that.

Resolved changing cname

mydomain_test.com/ibmcognos  to mydomain-test.com/ibmcognos 

It is crazy to have to loose to much time just for an underscore  ;D

http://connect.microsoft.com/IE/feedback/details/804339/cookie-handling-for-hosts-domains-with-the-underscore-character
http://www-01.ibm.com/support/docview.wss?uid=swg21112062

Hope this will help someone.

Bye  ;D