The default or "internal" network connections of RCE (informally called "LocalNet" connections) are designed for close collaboration within a working group, and are only intended to be used within trusted networks. If you require secure connections across the boundaries of trusted networks (especially across the internet), or collaborate with external partners, the encrypted and authenticated SSH Uplink connections should be used instead.

A default RCE installation does not open a network port for these connections unless explicitly configured to do so.

For a general overview of RCE's default network approach, please refer to the standard RCE User Guide (available at https://rcenvironment.de/pages/documentation/documentation.html for the latest release).

If RCE is configured to accept incoming network connections, the port number(s) to be used can be freely chosen within the range permitted by the operating system. As RCE should never be run with elevated privileges (SYSTEM, root, or equivalent), the effective range of usable ports is 1024 to 65535. Note that port values below 1024 are currently not explicitly refused by RCE, but will typically fail with a permission error. This may be changed to an explicit check in a future update.

Incoming connections can be restricted to certain IPv4 addresses. However, these filters are static, so this feature is only useful for either restricting connections to localhost for local multi-instance setups, or setting up networks between few, static, and long-living nodes. Both setups are fairly untypical, but may still be of use in certain situations.