Multimedia communications over packet switched networks - commonly referred to as Internet telephony - has generated immense interest in recent years. The International Telecommunication Union is currently developing the H.323 umbrella of standards for this purpose. In the H-323 standard, a gatekeeper is a control entity that performs functions such as address translation, bandwidth management etc. A H.323 terminal needs to discover a suitable gatekeeper and register with it. When a H.3232 terminal wishes to call another H.323 terminal, communication between the gatekeepers result in the determination of the transport layer address of the destination terminal for sending the connection setup message to. There is thus a need not only for terminals to discover gatekeepers but also for gatekeepers to discover other gatekeepers. In this paper, we propose a mechanism whereby terminals and gatekeepers can discover other gatekeepers. The proposed mechanisms result in efficient use of network bandwidth within the administrative domain. The security issues involved in such communications are discussed, and a proposal is made to establish a shared secret during the discovery process. Such a shared secret may be used for subsequent confidentiality or authentication of messages.