Trisqwall is a dedicated PC acting as a firewall for the COSI WiFi running Trisquel. It's primary purpose at the moment is to block popular game services during weekdays. These currently include:
Trisqwall is located at 188.8.131.52 and can be accessed remotely via SSH.
The firewall is built using FWBuilder, which means that any PC on the COSI network running FWBuilder can open this template and update/change the firewall remotely (must be renamed to .fwb):