Ignoring the Great Firewall of China

  • Richard Clayton
  • Steven J. Murdoch
  • Robert N. M. Watson
Part of the Lecture Notes in Computer Science book series (LNCS, volume 4258)


The so-called “Great Firewall of China” operates, in part, by inspecting TCP packets for keywords that are to be blocked. If the keyword is present, TCP reset packets (viz: with the RST flag set) are sent to both endpoints of the connection, which then close. However, because the original packets are passed through the firewall unscathed, if the endpoints completely ignore the firewall’s resets, then the connection will proceed unhindered. Once one connection has been blocked, the firewall makes further easy-to-evade attempts to block further connections from the same machine. This latter behaviour can be leveraged into a denial-of-service attack on third-party machines.


Transmission Control Protocol Intrusion Detection System Port Number Child Pornography Domain Name System 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2006

Authors and Affiliations

  • Richard Clayton
    • 1
  • Steven J. Murdoch
    • 1
  • Robert N. M. Watson
    • 1
  1. 1.Computer Laboratory, William Gates BuildingUniversity of CambridgeCambridgeUnited Kingdom

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