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Method of preventing TCP-based denial-of-service attacks on mobile devices

  • US 9,055,099 B2
  • Filed: 09/14/2007
  • Issued: 06/09/2015
  • Est. Priority Date: 08/08/2007
  • Status: Expired due to Fees
First Claim
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1. A method of preventing a Denial of Service (DoS) attack by checking flow of packets transmitted between a base station and a mobile station using a Transmission Control Protocol (TCP) protocol, the method comprising the steps of:

  • transmitting, at the mobile station, a connection request acknowledgement SYN/ACK

    1 packet to the base station when the base station transmits a connection request SYN packet for a TCP connection to the mobile station, and the mobile station receives the transmitted connection request SYN packet;

    transmitting, at the base station, an acknowledgement ACK

    2 packet corresponding to the connection request acknowledgement SYN/ACK

    1 packet to the mobile station when the transmitted connection request acknowledgement SYN/ACK

    1 packet is received;

    establishing the TCP connection when the mobile station receives the transmitted acknowledgement ACK

    2 packet; and

    determining that the established TCP connection is abnormal and terminating the established TCP connection if the mobile station receives a packet, in which a reset RST or connection request SYN flag is set, transmitted from the base station, wherein when the TCP connection is established, and then the mobile station cannot receive any packet during a previously set timeout period, the base station is determined to have abnormally terminated the TCP connection, and the mobile station safely terminates the TCP connection.

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