I have a program that runs as a service and a client that connects to that service to control it. The client accesses the service using the local loppback adapter at and ZoneAlarm says the program wants to connect to the internet. The loopback adapter is part of the local network.
I would rather not allow "the internet" to access either the service or have the client access "the internet" because is treated as an internet address.
ZoneAlarm should always treat the following address ranges as local by default, they're never internet addresses:
Whichever network mask the network adapter is set to

I'm not yet that much familiar with IPv6 and I haven't tested that one, but ::1 should also be part of the local network, if it isn't.

Also, the local IP and the loopback addresses should always be part of the trusted zone, I've never heard of or ::1 to lead to another machine, unless a forwarding service is running at the particular port (which would need to be granted trusted and/or internet access first).