Not able access internet in PS4

I purchased a PS4 1 TB system. But I am not able access internet. I am using a LAN connection. I have to login to the service provider portal once I open any browser. But PS4 doesn't give the option to enter any url to open the login portal. It only shows the screen "sign in to playstation network". But I can't sign in until I sign in to the Internet portal.

Any help with this would be highly appreciated.