When IP telephony devices that make use of an Internet protocol (IP) based private branch exchange (PBX) service provider resister with PBX service provider, they furnish local address information that indicates how they telephony devices can be reached directly for a telephony communication. This information is provided to other telephony devices within the same business or organization. As a result, the telephony devices within a business or organization can contact one another directly to setup and conduct telephony communications, without the need for such telephony communications to pass though assets of the IP based PBX service provider.