UDP Port Knocking

Host:

Port:

Data:

Test:

http://124.156.159.168:8080/hello

This link is not accessible before knocking

NOTE: Do not use a proxy to open this page, as UDP packets may not pass through the proxy.

Server Policy:

iptables \
  -i eth0 \
  -t raw --append PREROUTING \
  -p tcp --dport 8080 --syn \
  -m recent --name knocked ! --rcheck --seconds 600 \
  -j DROP

iptables \
  -i eth0 \
  -t raw --append PREROUTING \
  -p udp --dport 30000 \
  -m string --string "OpenSesame" --algo bm \
  -m recent --name knocked --set \
  -j DROP