This RFC summarizes the requirements for gateways to be used on networks supporting the DARPA Internet protocols. While it applies specifically to National Science Foundation research programs, the requirements are stated in a general context and are believed applicable throughout the Internet community. The purpose of this document is to present guidance for vendors offering products that might be used or adapted for use in an Internet application. It enumerates the protocols required and gives references to RFCs and other documents describing the current specification.