US Patent 7869394 Limiting data packet forwarding to trusted ports

This document describes tools that forward data packets to trusted ports and prevent data packets from egressing non-trusted ports. To do so, the tools receive a data packet having a destination address specifying that the data packet be forwarded to a set of ports associated with a domain. The tools identify a subset of the set of ports as trusted ports and forward the data packet to the subset. The tools prevent the data packet from egressing non-trusted ports of the set. In one embodiment, the tools may classify a port as trusted. To do so, the tools receive a configuration communication identifying trusted devices. The tools broadcast a request to the trusted devices and receive a reply from a reply device on a reply port. The tools determine that the reply device is one of the trusted devices and mark the reply port as a trusted port.