UDPQuiz

UDPQuiz is an eBPF program that runs on Linux to send back all udp packets as is. This makes it a perfect tool to test which udp ports have been firewalled on your network.

Visit https://udpquiz.com/ to try it out!

Running locally

# Replace eth0 with your interface name
export DEVICE=eth0

# Compile and load
make

# Once complete, the filter and qdisc can be removed
make clean

References

• Send ICMP Echo Replies using eBPF
• Bypassing Captive Portals
• tc direct action mode for BPF