Ospfv3 Authentication Using Ipsec - Dell S6100 Configuration Manual

OSPFv3 Authentication Using IPsec

OSPFv3 uses IPsec to provide authentication for OSPFv3 packets. IPsec authentication ensures security in the transmission of OSPFv3
packets between IPsec-enabled routers.
IPsec is a set of protocols developed by the internet engineering task force (IETF) to support secure exchange of packets at the IP layer.
IPsec supports two encryption modes: transport and tunnel.
• Transport mode — encrypts only the data portion (payload) of each packet, but leaves the header untouched.
• Tunnel mode — is more secure and encrypts both the header and payload. On the receiving side, an IPsec-compliant device decrypts
each packet.
NOTE: Dell Networking OS supports only Transport Encryption mode in OSPFv3 authentication with IPsec.
With IPsec-based authentication, Crypto images are used to include the IPsec secure socket application programming interface (API)
required for use with OSPFv3.
To ensure integrity, data origin authentication, detection and rejection of replays, and confidentiality of the packet, RFC 4302 and RFC 4303
propose using two security protocols — authentication header (AH) and encapsulating security payload (ESP). For OSPFv3, these two
IPsec protocols provide interoperable, high-quality cryptographically-based security.
• HA — IPsec authentication header is used in packet authentication to verify that data is not altered during transmission and ensures
that users are communicating with the intended individual or organization. Insert the authentication header after the IP header with a
value of 51. AH provides integrity and validation of data origin by authenticating every OSPFv3 packet. For detailed information about
the IP AH protocol, refer to RFC 4302.
• ESP — 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. Insert the ESP header after the IP header and before the next layer protocol header in Transport mode. It is
possible to insert the ESP header between the next layer protocol header and encapsulated IP header in Tunnel mode. However, Tunnel
mode is not supported in Dell Networking OS. For detailed information about 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.
You decide the set of IPsec protocols that are employed for authentication and encryption and the ways in which they are employed. When
you correctly implement and deploy IPsec, 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.
• To use IPsec, 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.
• You can only enable one security protocol (AH or ESP) at a time on an interface or for an area. Enable IPsec AH with the ipv6
ospf authentication command; enable IPsec ESP 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.
Open Shortest Path First (OSPFv2 and OSPFv3) 629