Concept Guide

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 condentiality 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 EMC 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 dierence between the two mechanisms is the extent of the coverage. ESP only protects IP header elds 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 aect users or hosts. AH and ESP are designed to be cryptographic
algorithm-independent.
OSPFv3 Authentication Using IPsec: Conguration Notes
OSPFv3 authentication using IPsec is implemented according to the specications in RFC 4552.
• To use IPsec, congure 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 congured 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 congured for an area is inherited by default on all interfaces in the area.
– The security policy congured on an interface overrides any area-level congured security for the area to which the interface is
assigned.
– The congured 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 trac on an OSPFv3 interface.
– There is no maximum AH or ESP header length because the headers have elds with variable lengths.
• Manual key conguration is supported in an authentication or encryption policy (dynamic key conguration using the internet key
exchange [IKE] protocol is not supported).
• In an OSPFv3 authentication policy:
– AH is used to authenticate OSPFv3 headers and certain elds 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.
– IPsec security associations (SAs) are supported only in Transport mode (Tunnel mode is not supported).
– ESP with null encryption is supported for authenticating only OSPFv3 protocol headers.
– ESP with non-null encryption is supported for full condentiality.
– 3DES, DES, AES-CBC, and NULL encryption algorithms are supported; encrypted and unencrypted keys are supported.
NOTE
: To encrypt all keys on a router, use the service password-encryption command in Global Conguration mode.
However, this command does not provide a high level of network security. To enable key encryption in an IPsec security policy at
an interface or area level, specify 7 for [key-encryption-type] when you enter the ipv6 ospf authentication
ipsec
or ipv6 ospf encryption ipsec command.
• To congure an IPsec security policy for authenticating or encrypting OSPFv3 packets on a physical, port-channel, or VLAN interface
or OSPFv3 area, perform any of the following tasks:
– Conguring IPsec Authentication on an Interface
– Conguring IPsec Encryption on an Interface
– Conguring IPsec Authentication for an OSPFv3 Area
678
Open Shortest Path First (OSPFv2 and OSPFv3)