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 the 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.
• 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:
Open Shortest Path First (OSPFv2 and OSPFv3) 649