Telefonaktiebolaget Lm Ericsson (Publ)

Peter Anders Nesz

Thomas Johansson

Michael Valentin Juhl

Illegitimate use of IP addresses is counteracted. A network () includes a switch () with ports (PPP) to subscribers (A) and a port (PN) to a core network () with DHCP servers (a,b). The switch includes a database (MACMAC), port numbers (PP) and VLAN identities (VLANVLAN) 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 (MM) for an IP address it is checked that it is a DHCP message with valid subscriber values (MACPVLAN). A respond (MM) 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 (MACPVLANIPT). 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.

Method and arrangement for preventing illegitimate use of IP addresses

Illegitimate use of IP addresses is counteracted. A network () includes a switch () with ports (PPP) to subscribers (A) and a port (PN) to a core network () with DHCP servers (a,b). The switch includes a database (MACMAC), port numbers (PP)) and VLAN identities (VLANVLAN) 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 (MM) for an IP address it is checked that it is a DHCP message with valid subscriber values (MACPVLAN). A respond (MM) 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 (MACPVLANIPT). 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.

Growing community of inventors

Årsta, Sweden

Peter Anders Nesz