# Trust Boundaries The *trust boundary* of a network defines where devices trust/don't trust the QoS markings of received messages. If the markings are **trusted**, the device will forward the message without changing the markings. If the markings **aren't trusted**, the device will change the markings according to the configured policy.

If an IP phone is connected to the switch port, it is recommended to move the trust boundary to the IP phones. This is done via configuration on the switch port connected to the IP phone. If a user marks their PC's traffic with a high priority, the marking will be changed (not trusted).

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