Dell Force10 Z9000 FTOS Configuration Guide for Z9000 System - Page 660

www.dell.com | support.dell.com • The encapsulating security payload encapsulates data, enabling the protection of data that follows in the datagram. ESP provides authentication and confidentiality of every packet. The ESP extension header is designed to provide a combination of security services for both IPv4 and IPv6. The ESP header is inserted after the IP header and before the next layer protocol header in transport mode. It is possible that the ESP header is inserted between the next layer protocol header and encapsulated IP header in tunnel mode. The tunnel mode is not supported in FTOS. For detailed information on the IP ESP protocol, refer to RFC 4303. In OSPFv3 communication, IPsec provides security services between a pair of communicating hosts or security gateways using either AH or ESP. In an authentication policy on an interface or in an OSPF area, AH and ESP are used alone; in an encryption policy, AH and ESP may be used together. The difference between the two mechanisms is the extent of the coverage. ESP only protects IP header fields if they are encapsulated by ESP. The set of IPsec protocols that are employed for authentication and encryption and the ways in which they are employed is user-dependent. When IPsec is correctly implemented and deployed, it does not adversely affect users or hosts. AH and ESP are designed to be cryptographic algorithm-independent. OSPFv3 Authentication using IPsec: Configuration Notes OSPFv3 authentication using IPsec is implemented according to the specifications in RFC 4552, including: • To use IPsec, you configure an authentication (using AH) or encryption (using ESP) security policy on an interface or in an OSPFv3 area. Each security policy consists of a security policy index (SPI) and the key used to validate OSPFv3 packets. After IPsec is configured for OSPFv3, IPsec operation is invisible to the user. • Only one security protocol (AH or ESP) can be enabled at a time on an interface or for an area. IPsec AH is enabled with the ipv6 ospf authentication command; IPsec ESP is enabled with the ipv6 ospf encryption command. • The security policy configured for an area is inherited by default on all interfaces in the area. • The security policy configured on an interface overrides any area-level configured security for the area to which the interface is assigned. • The configured authentication or encryption policy is applied to all OSPFv3 packets transmitted on the interface or in the area. The IPsec security associations (SAs) are the same on inbound and outbound traffic on an OSPFv3 interface. • There is no maximum AH or ESP header length because the headers have fields with variable lengths. • Manual key configuration is supported in an authentication or encryption policy (dynamic key configuration using the Internet Key Exchange (IKE) protocol is not supported). • In an OSPFv3 authentication policy: • AH is used to authenticate OSPFv3 headers and certain fields in IPv6 headers and extension headers. • MD5 and SHA1 authentication types are supported; encrypted and unencrypted keys are supported. • In an OSPFv3 encryption policy: • Both encryption and authentication are used. 660 | Open Shortest Path First (OSPFv2 and OSPFv3)