Scenario: "Taipei": Come a-knocking
Description: There is a web server on port :80 protected with Port Knocking. Find the one "knock" needed (sending a SYN to a single port, not a sequence) so you can curl localhost.
Test: Executing curl localhost returns a message with md5sum fe474f8e1c29e9f412ed3b726369ab65. (Note: the resulting md5sum includes the new line terminator: echo $(curl localhost))
Time to Solve: 15 minutes.