HP 6125XLG R2306-HP 6125XLG Blade Switch Security Configuration Guide - Page 231

Configuring IKE, Overview, IKE negotiation process

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Configuring IKE Unless otherwise specified, the term "IKE" in this chapter refers to IKEv1. Overview Built on a framework defined by ISAKMP, Internet Key Exchange (IKE) provides automatic key negotiation and SA establishment services for IPsec, dramatically simplifying the configuration and maintenance of IPsec. IKE is not intended solely for IPsec, but it is widely used for IPsec. This chapter describes how to use IKE for IPsec. IKE provides the following benefits for IPsec: • Automatically negotiates IPsec parameters. • Performs DH exchanges to calculate shared keys, making sure each SA has a key independent of other keys. • Automatically negotiates SAs when the sequence number in the AH or ESP header overflows, making sure IPsec can provide the anti-replay service by using the sequence number. As shown in Figure 75, IKE negotiates SAs for IPsec and transfers the SAs to IPsec, and IPsec uses the SAs to protect IP packets. Figure 75 Relationship between IKE and IPsec IKE negotiation process IKE negotiates keys and SAs for IPsec in two phases: 1. Phase 1-The two peers establish an IKE SA, a secure, authenticated channel for communication. In this phase, two modes are available: main mode and aggressive mode. 2. Phase 2-Using the IKE SA established in phase 1, the two peers negotiate to establish IPsec SAs. 222

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222
Configuring IKE
Unless otherwise specified, the term "IKE" in this chapter refers to IKEv1.
Overview
Built on a framework defined by ISAKMP, Internet Key Exchange (IKE) provides automatic key negotiation
and SA establishment services for IPsec, dramatically simplifying the configuration and maintenance of
IPsec.
IKE is not intended solely for IPsec, but it is widely used for IPsec. This chapter describes how to use IKE
for IPsec.
IKE provides the following benefits for IPsec:
Automatically negotiates IPsec parameters.
Performs DH exchanges to calculate shared keys, making sure each SA has a key independent of
other keys.
Automatically negotiates SAs when the sequence number in the AH or ESP header overflows,
making sure IPsec can provide the anti-replay service by using the sequence number.
As shown in
Figure 75
, IKE negotiates SAs for IPsec and transfers the SAs to IPsec, and IPsec uses the SAs
to protect IP packets.
Figure 75
Relationship between IKE and IPsec
IKE negotiation process
IKE negotiates keys and SAs for IPsec in two phases:
1.
Phase 1
—The two peers establish an IKE SA, a secure, authenticated channel for communication.
In this phase, two modes are available: main mode and aggressive mode.
2.
Phase 2
—Using the IKE SA established in phase 1, the two peers negotiate to establish IPsec SAs.