> # Configuring IPsec Network Security

> IP security (IPsec) protocol is a framework of open standards that provides data confidentiality, data integrity, and data authentication between participating peers. It is developed by the Internet Engineering Task Force (IETF). IPsec provides security services at the IP layer, including protecting one or more data flows between a pair of hosts, between a pair of security gateways, or between a security gateway and a host. The overall IPsec implementation is the latest version of RFC 2401. Cisco NX-OS IPsec implements RFC 2402 through RFC 2410.

> IPsec uses the Internet Key Exchange (IKE) protocol to handle protocol and algorithm negotiation and to generate the encryption and authentication keys used by IPsec. While IKE can be used with other protocols, its initial implementation is with the IPsec protocol. IKE provides authentication of the IPsec peers, negotiates IPsec security associations, and establishes IPsec keys. IKE uses RFCs 2408, 2409, 2410, and 2412, and additionally implements the draft-ietf-ipsec-ikev2-16.txt draft.

> The term IPsec is sometimes used to describe the entire protocol of IPsec data services and IKE security protocols and is other times used to describe only the data services.

> This chapter includes the following topics:

> - Information About IPsec Network Security
> - Prerequisites for IPsec
> - Guidelines and Limitations
> - Default Settings
> - Enabling IPsec Using FCIP Wizard
> - Configuring IPsec and IKE Manually
> - Configuring Crypto
> - Field Descriptions for IPsec

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