Patent ID: 7590733

Claim:
A method of controlling access to a protected network, the method comprising: receiving a DHCPDISCOVER packet at an input of a DHCP server via a router from an endpoint having an address, the router including an access control list characterizing a restricted subnet and a less-restricted subnet of the protected network; determining if the address within the DHCPDISCOVER packet received at the input is included in a list of addresses qualified to access the restricted subnet of the protected network; altering the DHCPDISCOVER packet received at the input responsive to whether the address is included in the list of addresses qualified to access the restricted subnet; passing the altered DHCPDISCOVER packet to computing instructions included in the DHCP server, the computing instructions configured to generate a DHCPOFFER packet; generating the DHCPOFFER packet responsive to the alteration of the DHCPDISCOVER packet, the DHCPOFFER packet including an IP address associated with the restricted subnet if the address is included in the list of addresses qualified to access the restricted subset, the DHCPOFFER packet including an IP address associated with the less-restricted subnet if the address is not in the list of addresses qualified to access the restricted subset, the IP address associated with the restricted subnet having access to the restricted subset responsive to the access control list.