By default, if you use Firefox as default browser, and you open the Software Center then Click on
“Find Additional applications from the Software Catalog”, you will get prompted with a Authentication prompt
This is simply due to the fact that Firefox does not transmit the logged on user credentials by default, where Internet Explorer does.
In order to get the same functionality, add the following entry to your mozilla.cfg file
Of course, replace the value with your Sccm server FQDN.
Next time you launch the software catalog, you won’t be prompted for credentials.
The only thing you have to do is enable Silverlight, and the functionality will be the same as with Internet Explorer.