Describes how to implement virtual private networks (VPNs) based on authentication, encryption, and the exchange of security keys, as stated in the IP Security Architecture (IPSec) standard and draft documents. Scenarios explain how to set up IP tunneling via existing IP networks and the Internet to implement secure and private conversations over public networks, illustrating point-to-point, branch office, and remote user environments. An outlook is provided on further development in this area, including certificate and key management frameworks such as Internet Key Exchange. Annotation c. by Book News, Inc., Portland, Or.