# Fun with The Great Firewall

DevFeed: [Fun with The Great Firewall](<https://devfeed.tech/articles/fun-with-the-great-firewall-38924.md>)

Original publisher: [Read original article](<https://idea.popcount.org/2013-07-11-fun-with-the-great-firewall>)

Author: Marek

Published: 2013-07-10T22:00:00Z

Content type: opinion

Language: en

Sources: [Marek Majkowski](<https://devfeed.tech/sources/marek-majkowski.md>)

Topics: [Firewall](<https://devfeed.tech/topics/firewall.md>), [tor](<https://devfeed.tech/topics/tor.md>), [TCP/IP](<https://devfeed.tech/topics/tcp-ip.md>)

Tags: [firewall](<https://devfeed.tech/tags/firewall.md>), [iptables](<https://devfeed.tech/tags/iptables.md>), [payload](<https://devfeed.tech/tags/payload.md>), [port](<https://devfeed.tech/tags/port.md>), [servers](<https://devfeed.tech/tags/servers.md>), [ssl](<https://devfeed.tech/tags/ssl.md>), [tcp-ip](<https://devfeed.tech/tags/tcp-ip.md>), [tor](<https://devfeed.tech/tags/tor.md>)

## AI overview

The article describes observations of how China's Great Firewall probes and blocks Tor bridges. It reports that detected Tor bridges may have their IP-and-port tuples blocked for hours, while later probing behavior appeared to vary over time and was not fully understood.

## Source excerpt

Fun with The Great Firewall I was playing with the Tor Project and decided to understand how the Chinese block Tor servers. Philipp Winter wrote an amazing paper on that subject. He noticed The Great Firewall of China is actively scanning services and if it detects a Tor bridge it blocks the ip:port tuple for a few hours. TCP/IP When a port gets censored "ACK" packets are dropped by the GFW. Most importantly and .