None of the machines inside the spaceBridge network are running a local firewall. All filtering is performed by the router itself.
With the exception the router itself and the laptop, all stations have the following firewall exeptions...
Source Address/Network = 188.8.131.52/22 (PTC Wired Network); Allow TCP 5900 (VNC), Allow TCP 3389 (RDP)
When using StaticNAT, this must be set up using the Adminstration|Commands tab in the router's GUI, in order to insert these as iptables rules upon boot.
A backup/text file containing the list of inserted rules is here...