R0106-HP MSR Router Series Security Configuration Guide(V7)

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Configuring IPsec
In this chapter, "MSR2000" refers to MSR2003. "MSR3000" collectively refers to MSR3012, MSR3024,
MSR3044, MSR3064. "MSR4000" collectively refers to MSR4060 and MSR4080.
Overview
IP Security (IPsec) is defined by the IETF to provide interoperable, high-quality, cryptography-based
security for IP communications. It is a Layer 3 VPN technology that transmits data in a secure channel
established between two endpoints (such as two security gateways). Such a secure channel is usually
called an IPsec tunnel.
IPsec is a security framework that comprises the following protocols and algorithms:
• Authentication Header (AH).
• Encapsulating Security Payload (ESP).
• Internet Key Exchange (IKE).
• Algorithms for authentication and encryption.
AH and ESP are security protocols that provide security services. IKE performs automatic key exchange.
For more information about IKE, see "Configuring IKE."
I
Psec provides the following security services for data packets in the IP layer:
• Confidentiality—The sender encrypts packets before transmitting them over the Internet, protecting
the packets from being eavesdropped en route.
• Data integrity—The receiver verifies the packets received from the sender to make sure they are not
tampered with during transmission.
• Data origin authentication—The receiver verifies the authenticity of the sender.
• Anti-replay—The receiver examines packets and drops outdated and duplicate packets.
IPsec delivers the following benefits:
• Reduced key negotiation overhead and simplified maintenance by supporting the IKE protocol. IKE
provides automatic key negotiation and automatic IPsec security association (SA) setup and
maintenance.
• Good compatibility. You can apply IPsec to all IP-based application systems and services without
modifying them.
• Encryption on a per-packet rather than per-flow basis. Per-packet encryption allows for flexibility
and greatly enhances IP security.
Security protocols and encapsulation modes
Security protocols
IPsec comes with two security protocols, AH and ESP. They define how to encapsulate IP packets and the
security services that they can provide.
• AH (protocol 51) defines the encapsulation of the AH header in an IP packet, as shown in Figure 76.
AH c
an provide data origin authentication, data integrity, and anti-replay services to prevent data