which attempts to restrict their behavior. In addi- tion, the Internet model transforms the locations at which many services are performed. In general, end systems are assumed to be much more intelligent than in the traditional telephone model; thus, many services which tradition- ally had to reside within the network can be moved out to the edges, without requiring any explicit support for them within the network. Other services can be performed by widely separated specialized servers which result in call setup information traversing paths which might be extremely indirect when compared with the physical network's actual topology. Most of the services and service features of ITU-T Q.1211 can be provided by IETF's draft signaling standards for Internet Telephony, SIP [2] and, for some specialized features, its Call Control extensions [3]. ENUM provides the capability to translate an E.164 telephone number into a set of URIs using DNS. This capability has different uses depending on the applications being used and, in the case of voice services, the technology available at the source and destination of the communication. For voice services, ENUM allows easy end-user identification and interwork- ing between terminals on PSTN and IP-based networks. It may also allow for the implementation of more advanced services. C 2009 by Taylor & Francis Group, LLC Secure Intelligent SIP Services TRIP was engineered as a tool for inter-domain exchange of telephone rout- ing information. However, it can also be used as a means for gateways and soft switches to export their routing information to a Location Server (LS), which may be co-resident with a proxy or gatekeeper. With these protocols is it possible to implant a voice services that will be exploited by an IP client or PSTN? Some engineers have developed VoIP systems based on the SIP protocol; Astol, that interconnects Internet and Fax, Cisco Systems developed routers of SIP messages that interconnect to PSTN, Eurotelstat developed equipment- based SIP that enables call tr