To enable proxy add the [Proxy] section to the configuration file.
In this section set these options:

Proxy Enabled=1
Internal Network Address=...
Internal Network Mask=...

The last two options must indicate the network address and netmask of the
network behind the proxy. For example if you want to proxy the
communications between an ip of the network 138.203.x.y and an external
ip, you must set the option as follow:

Internal Network Address=138.203.0.0
Internal Network Mask=255.255.0.0

If there is a firewall you can close all the port you want on all computers
except on the coputers where reside opengatekeeper. The gatekeeper use dynamic
allocated udp and tcp ports over the port number 1024. Further it use tcp
port 1719 for RAS communications.

