Moby is an open source container framework that is a key component of Docker Engine, Docker Desktop, and other distributions of container tooling or runtimes. Moby's networking implementation allows for many networks, each with their own IP address range and gateway, to be defined. This feature is frequently referred to as custom networks, as each network can have a different driver, set of parameters and thus behaviors. When creating a network, the `--internal` flag is used to designate a network as _internal_. The `internal` attribute in a docker-compose.yml file may also be used to mark a network _internal_, and other API clients may specify the `internal` parameter as well. When containers with networking are created, they are assigned unique network interfaces and IP addresses. The host serves as a router for non-internal networks, with a gateway IP that provides SNAT/DNAT to/from container IPs. Containers on an internal network may communicate between each other, but are precl…