ISP Authentication - Other Methods
Anything that has an IP address will have a MAC (Media Access Control) address. MAC addresses are unique to each piece of networking equipment (at least they're supposed to be... more below) and are used in the IP address assignment process. The MAC address (also known as an "Adapter" or "Ethernet" address) is composed of twelve hexadecimal characters. To avoid address duplication, ranges of addresses are assigned to network equipment manufacturers, who are charged with setting up the proper systems to ensure that address assignments are not duplicated.
MAC addresses are not case sensitive, so the letters that are used (A-F) can be either upper or lower case.
MAC address authentication used to be very commonly used. But routers evolved to allow setting the WAN MAC address to whatever you wanted either by automatically "cloning" the MAC address of a computer that's attached to it, or letting you manually enter the MAC address. This greatly reduced the effectiveness of this authentication method.
The Host Name method was used primarily by the now defunct BSP @Home. It requires that the Host Name (Windows calls this the "Computer Name") of the connected computer be set to a specific, long name. Many routers continue to include the ability to set the Host Name, even though @Home has long since gone.
Known more as Microsoft's VPN protocol, PPTP authentication is used by some ISPs instead of PPPoE. The setup screens and parameters look very similar to PPPoE.
Another username / password authentication system used by the large Australian BSP.