The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 09, 2011
Filed:
Nov. 06, 2002
Peter Nesz, Arsta, SE;
Thomas Johansson, Haninge, SE;
Michael Valentin Juhl, Silkeborg, DK;
Telefonaktiebolaget L M Ericsson (Publ), Stockholm, SE;
Abstract
Illegitimate use of IP addresses is counteracted. A network () includes a switch () with ports (P,P,P) to subscribers (A) and a port (PN) to a core network () with DHCP servers (). The switch includes a database (MAC, MAC), port numbers (P, P)) and VLAN identities (VLAN, VLAN) for the subscribers (A) and the filter has a list over trusted DHCP servers. Initially onlY DHCP messages from the subscribers are allowed. When the subscriber () requests (M, M) for an IP address it is checked that it is a DHCP message with valid subscriber values (MAC, P, VLAN). A respond (M, M) with an allocated IP address (IP) and lease time interval (T) is checked to come from a trusted DHCP server. If so, a list in the filter () with correct information is dynamically generated (MAC, P, VLAN, IP, T). A message (M) from the subscriber () with false IP address is discarded by the filter. Attempts by the subscriber to use false IP address are counted and a warning signal is generated.