A TCP service is identified not only by the IP address of the machine it is running on, but also by a small integer, the TCP port it is listening on. Normally, web servers listen on port 80, but it is not uncommon to have them listen on different ports; Polipo’s internal web server, for example, listens on port 8123 by default.
allowedPorts contains the list of ports that
Polipo will accept to connect to on behalf of clients; it defaults to
‘80-100, 1024-65535’. Set this variable to ‘1-65535’ if your
clients (and the web pages they consult!) are fully trusted. (The
allowedPorts is not considered for tunnelled
connections; see Tunnelling connections).