DHCP enhancements for MAC-layer user authentication and access control

Intranet management is becoming as critical as intrusion detection since misconfiguration of local network parameters may jeopardize the whole intranet. In our previous paper [1], a MAC (Medium Access Control) layer user authentication scheme combining DHCP (Dynamic Host configuration Protocol) [2] server and packet filtering firewalls was proposed for better control of local resources and Internet accesses. In this paper, DHCP mechanism will be further strengthened by the newly proposed DHCP options DHCPINFORM [2] and DHCP Reconfigure Extension [3]. An access control list (ACL) was maintained at the firewall according to the states of DHCP leases and packets from intranet hosts. Hosts not obeying our DHCP-based management scheme will be restricted Internet access by firewall.