Configuring Ipsec; Overview; Basic Concepts - HP 12500 Series Configuration Manual

Configuring IPsec

The term "router" in this chapter refers to both routers and Layer 3 switches.
IPsec is available only on Ethernet interface cards.

Overview

IP Security (IPsec) is a security framework defined by the IETF for securing IP communications. It is a Layer
3 VPN technology that transmits data in a secure tunnel established between two endpoints.
IPsec provides the following security services in insecure network environments:
Confidentiality—The sender encrypts packets before transmitting them over the Internet, protecting
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the packets from being eavesdropped en route.
Data integrity—The receiver verifies the packets received from the sender to make sure they are not
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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Anti-replay—The receiver examines packets and drops outdated and duplicate packets.
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IPsec delivers the following benefits:
Reduced key negotiation overheads and simplified maintenance by supporting the IKE protocol.
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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
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and greatly enhances IP security.
IPsec comprises a set of protocols, including Authentication Header (AH), Encapsulating Security
Payload (ESP), Internet Key Exchange (IKE), and algorithms for authentication and encryption. AH and
ESP provides security services and IKE performs automatic key exchange. For more information about IKE,
see "Configuring
IPsec can protect both IPv4 and IPv6 packets.

Basic concepts

Security protocols
IPsec comes with two security protocols:
AH (protocol 51)—Provides data origin authentication, data integrity, and anti-replay services by
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adding an AH header to each IP packet. AH is suitable only for transmitting non-critical data
because it cannot prevent eavesdropping, although it can prevent data tampering. AH supports
authentication algorithms such as MD5 and SHA- 1 .
• ESP (protocol 50)—Provides data encryption as well as data origin authentication, data integrity,
and anti-replay services by inserting an ESP header and an ESP trailer in IP packets. Unlike AH, ESP
encrypts data before encapsulating the data to guarantee data confidentiality. ESP supports
IKE."
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