Method and arrangement for preventing illegitimate use of IP addresses
US7996537B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 6, 2002 |
| Grant date | Aug 9, 2011 |
| Priority date | — |
| Expiry date | Sep 20, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L69/16
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Illegitimate use of IP addresses is counteracted. A network (1) includes a switch (5) with ports (P1,P2,P3) to subscribers (6,6A) and a port (PN) to a core network (2) with DHCP servers (4, 4a,4b). The switch includes a database (MAC1, MAC2), port numbers (P1, P2)) and VLAN identities (VLAN1, VLAN2) for the subscribers (6, 6A) and the filter has a list over trusted DHCP servers. Initially onlY DHCP messages from the subscribers are allowed. When the subscriber (6) requests (M1, M3) for an IP address it is checked that it is a DHCP message with valid subscriber values (MAC1, P1, VLAN1). A respond (M2, M4) with an allocated IP address (IP1) and lease time interval (T1) is checked to come from a trusted DHCP server. If so, a list in the filter (9) with correct information is dynamically generated (MAC1, P1, VLAN1, IP1, T1). A message (M5) from the subscriber (6) 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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.