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1.1. Summary of Contents of Document

This document specifies the base architecture for IPsec-compliant systems. It describes how to provide a set of security services for traffic at the IP layer, in both the IPv4 [Pos81a] and IPv6 [DH98] environments. This document describes the requirements for systems that implement IPsec, the fundamental elements of such systems, and how the elements fit together and fit into the IP environment. It also describes the security services offered by the IPsec protocols, and how these services can be employed in the IP environment. This document does not address all aspects of the IPsec architecture. Other documents address additional architectural details in specialized environments, e.g., use of IPsec in Network Address Translation (NAT) environments and more comprehensive support for IP multicast. The fundamental components of the IPsec security architecture are discussed in terms of their underlying, required functionality. Additional RFCs (see Section 1.3 for pointers to other documents) define the protocols in (a), (c), and (d).

  • a. Security Protocols -- Authentication Header (AH) and Encapsulating Security Payload (ESP)
  • b. Security Associations -- what they are and how they work, how they are managed, associated processing
  • c. Key Management -- manual and automated (The Internet Key Exchange (IKE))
  • d. Cryptographic algorithms for authentication and encryption

This document is not a Security Architecture for the Internet; it addresses security only at the IP layer, provided through the use of a combination of cryptographic and protocol security mechanisms.

The spelling "IPsec" is preferred and used throughout this and all related IPsec standards. All other capitalizations of IPsec (e.g., IPSEC, IPSec, ipsec) are deprecated. However, any capitalization of the sequence of letters "IPsec" should be understood to refer to the IPsec protocols.

The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD, SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this document, are to be interpreted as described in RFC 2119 [Bra97].