Dell S4820T, Configuration Manual

Page: 720 / 1178

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:
– 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.
– 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 confidentiality.
– 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 Configuration 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 configure 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:
720
Open Shortest Path First (OSPFv2 and OSPFv3)