734 | Open Shortest Path First (OSPFv2 and OSPFv3)w w w . d e l l . c o m | s u p p o r t . d e l l . c o m OSPFv3 Authentication Using IPsecOSPFv3 Authentication Using IPsec is supported only on platform: etStarting in release 8.4.2.0, OSPFv3 uses the IP Security (IPsec) to provide authentication for OSPFv3packets. IPsec authentication ensures security in the transmission of OSPFv3 packets betweenIPsec-enabled routers.IPsec is a set of protocols developed by the IETF to support secure exchange of packets at the IP layer.IPsec supports two encryption modes: Transport and Tunnel. Transport mode encrypts only the dataportion (payload) of each packet, but leaves the header untouched. The more secure Tunnel mode encryptsboth the header and the payload. On the receiving side, an IPsec-compliant device decrypts each packet.With IPsec-based authentication, crypto images are used to include the IPsec secure socket applicationprogramming interface (API) required for use with OSPFv3.To ensure integrity, data origin authentication, detection and rejection of replays, and confidentiality of thepacket, RFC 4302 and RFC 4303 propose using two security protocols - AH (authentication header) andESP (encapsulating security payload). For OSPFv3, these two IPsec protocols provide interoperable,high-quality cryptographically-based security.• The IPsec authentication header is used in packet authentication to verify that data is not altered duringtransmission and ensures that users are communicating with the intended individual or organization.The authentication header is inserted after the IP header with a value of 51. AH provides integrity andvalidation of data origin by authenticating every OSPFv3 packet. For detailed information on the IPAH protocol, refer to RFC 4302.• The encapsulating security payload encapsulates data, enabling the protection of data that follows inthe datagram. ESP provides authentication and confidentiality of every packet. The ESP extensionheader is designed to provide a combination of security services for both IPv4 and IPv6. The ESPheader is inserted after the IP header and before the next layer protocol header in transport mode. It ispossible that the ESP header is inserted between the next layer protocol header and encapsulated IPheader in tunnel mode. The tunnel mode is not supported in FTOS. For detailed information on the IPESP protocol, refer to RFC 4303.In OSPFv3 communication, IPsec provides security services between a pair of communicating hosts orsecurity 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 differencebetween the two mechanisms is the extent of the coverage. ESP only protects IP header fields if they areencapsulated by ESP.The set of IPsec protocols that are employed for authentication and encryption and the ways in which theyare employed is user-dependent. When IPsec is correctly implemented and deployed, it does not adverselyaffect users or hosts. AH and ESP are designed to be cryptographic algorithm-independent.Note: FTOS supports only transport encryption mode in OSPFv3 authentication with IPsec.
