Configuring ipsec, Overview – H3C Technologies H3C S6300 Series Switches User Manual
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Configuring IPsec
The term "interface" in this chapter collectively refers to Layer 3 interfaces, including VLAN interfaces.
CAUTION:
•
If you configure both IPsec and QoS on an interface, make sure the IPsec traffic classification rules match
the QoS traffic classification rules. If the rules do not match, QoS might classify the packets of one IPsec
SA to different queues, causing packets to be sent out of order. When IPsec anti-replay is enabled, IPsec
will drop the incoming packets that are out of the anti-replay window, resulting in packet loss. IPsec
traffic classification rules are determined by the referenced ACL rules. For information about QoS
classification rules, see
ACL and QoS Configuration Guide.
•
ACLs for IPsec take effect only on traffic that is generated by the device and traffic that is destined for the
device. They do not take effect on traffic forwarded through the device.
Overview
IP Security (IPsec) is defined by the IETF to provide interoperable, high-quality, cryptographically-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 "
IPsec 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Anti-replay—The receiver examines packets and drops outdated and duplicate packets.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.