An engineer is configuring a customer's environment for Jabber user over mobile and remote access. The customer's internal domain. Which Jabber parameter defines the external service discovery…

UPN discovery enabled is a parameter that controls whether Jabber uses the user's UPN suffix as the service discovery domain - it does not statically define an external domain.

ExcludeServices is a parameter used to disable specific Jabber services (such as voicemail or conferencing), not to define the service discovery domain.

ServicesDomain sets the domain for internal UC service discovery, not the external domain used when the client is outside the corporate network over MRA.

VoiceServicesDomain is the Jabber configuration parameter that explicitly sets the domain Jabber queries for external DNS SRV records (_cisco-uds, _collab-edge, etc.) during service discovery outside the corporate network. It is used when the external domain differs from the user's email domain or UPN, allowing administrators to statically point Jabber to the correct Expressway-E for MRA connectivity.