The firewall filter driver (FWIP.SYS) is a Ring 0 driver that examines all inbound and outbound IP traffic, and acts on it according to the rules specified in the firewall configuration. This process forms the basis of the firewall's operation.

In order to use the firewall, this driver must be loaded in CONFIG.SYS with the line

    DEVICE=x:\MPTN\PROTOCOL\FWIP.SYS

where x is the letter of the drive or volume on which Networking (MPTS) is installed.