(19)
(11) EP 1 401 160 A8

(12) CORRECTED EUROPEAN PATENT APPLICATION
published in accordance with Art. 158(3) EPC

(48) Corrigendum issued on:
07.07.2004 Bulletin 2004/28

(43) Date of publication:
24.03.2004 Bulletin 2004/13

(21) Application number: 02722781.8

(22) Date of filing: 25.04.2002
(51) International Patent Classification (IPC)7H04L 12/56
(86) International application number:
PCT/JP2002/004139
(87) International publication number:
WO 2002/089426 (07.11.2002 Gazette 2002/45)
(84) Designated Contracting States:
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR

(30) Priority: 27.04.2001 JP 2001133290

(71) Applicants:
  • NTT Data Corporation
    Tokyo 135-6033 (JP)
  • Cyber Solutions Inc.
    Sendai-shi, Miyagi-ken 989-3204 (JP)

(72) Inventors:
  • OHTANI, Hisamichi, c/o NTT Data Corporation
    Koto-ku, Tokyo 135-6033 (JP)
  • HOJO, Takeshi, c/o NTT Data Corporation
    Koto-ku, Tokyo 135-6033 (JP)
  • IWATA, Keiichi, c/o NTT Data Corporation
    Koto-ku, Tokyo 135-6033 (JP)
  • KEENI MANSFIELD, Glenn, c/o Cyber Solutions, Inc.
    Aoba-ku/Sendai-shi, Miyagi-ken 989-3204 (JP)

(74) Representative: Poulin, GĂ©rard 
BREVALEX 3, rue du docteur Lancereaux
75008 Paris
75008 Paris (FR)

   


(54) PACKET TRACING SYSTEM


(57) The purpose of the present invention is supplying a packet tracing system which can trace a route of a packet using existing network components. Packet printing devices 1a, 1b, and 1c generate packet identifying information for each packet which transmits through the communication line and write the packet identifying information to a storage part. An IDS 3 detects suspicious packets in a network under surveillance. A management system which receives a suspicious packet in a network generates a hash value for the suspicious packet and sends a request for examination which contains the hash value to the packet printing devices 1a, 1b and 1c. The packet printing devices 1a, 1b and 1c examine an internal storage part and send a result of examination to the management system 2. The management system 2 obtains a transmission route of the suspicious packet to be traced and by the result of examination and information of network construction.