Most of Voice over IP(VoIP) systems are deployed using SIP protocol and based in a client-server architecture. A lot of people and companies could be benefited if the system did not require the configuration and maintenance of central servers. Some proposals are found in the literature. In order to improve the efficiency of such approaches and to provide a complete self-configuring service of IP telephony, we suggest a new solution based on the P2P algorithm Kademlia. According with the results of our experiments, our approach has a better performance when network experiences different kind of delays due to the fact that Kademlia supports concurrent searches, improving the latency in user location, and providing a faster call establishment.