Hi,
I created a cognos multi-page portlet and put it into oracle webcenter portal(URL link), and it woks fine.
However, I still need to login cognos from Oracle webcenter portal in order to access reports. Is there any way to make it auto login?
If the Cognos credentials are via Windows (Active Directory), you should probably take a look at single signon, which is implemented with server-side configuration so you'll need cooperation from whoever takes care of your server(s).
You can embed user credentials in a URL, but that is a huge gaping security exposure I would not recommend even considering.