Broadband Connection for Standard User

Currently, I had set up a broadband connection for my account as the
administrator; I would like to allow my guest (as standard user) to be able
to use the SAME (I only have one connection) broadband connection to connect
to the internet as well.

As the administrator, I had tried to check the option of "Save this user
name and password for the following users: Anyone who uses this computer"
many times before this (under my connection screen), but still it did NOT
solve the problem.

I would really appreciate it if any of you can please assist me in addresing
the issue above, thank you. Hope the issue can be solved as soon as possible