When Open Shortest Path First version 3 (OSPFv3) runs on IPv6, OSPFv3 requires the IPv6 encapsulating security payload (ESP) header or IPv6 authentication header to ensure integrity, authentication, and confidentiality of routing exchanges. IPv6 ESP extension headers can be used to provide authentication and confidentiality to OSPFv3.
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Prerequisites for OSPFv3 IPSec ESP Encryption and Authentication
Configure the IP Security (IPsec) secure socket application program interface (API) on OSPFv3 in order to enable authentication and encryption.
Information About OSPFv3 IPSec ESP Encryption and Authentication
In order to ensure that OSPFv3 packets are not altered and re-sent to the device, causing the device to behave in a way not desired by its system administrators, OSPFv3 packets must be authenticated. OSPFv3 uses the IPsec secure socket API to add authentication to OSPFv3 packets. This API supports IPv6.
OSPFv3 requires the use of IPsec to enable authentication. Crypto images are required to use authentication, because only crypto images include the IPsec API needed for use with OSPFv3.
In OSPFv3, authentication fields have been removed from OSPFv3 packet headers. When OSPFv3 runs on IPv6, OSPFv3 requires the IPv6 authentication header (AH) or IPv6 ESP header to ensure integrity, authentication, and confidentiality of routing exchanges. IPv6 AH and ESP extension headers can be used to provide authentication and confidentiality to OSPFv3.
To use the IPsec AH, you must enable the
ipv6ospfauthentication command. To use the IPsec ESP header, you must enable the
ipv6ospfencryption command. The ESP header may be applied alone or in combination with the AH, and when ESP is used, both encryption and authentication are provided. Security services can be provided between a pair of communicating hosts, between a pair of communicating security gateways, or between a security gateway and a host.
To configure IPsec, you configure a security policy, which is a combination of the security policy index (SPI) and the key (the key is used to create and validate the hash value). IPsec for OSPFv3 can be configured on an interface or on an OSPFv3 area. For higher security, you should configure a different policy on each interface configured with IPsec. If you configure IPsec for an OSPFv3 area, the policy is applied to all of the interfaces in that area, except for the interfaces that have IPsec configured directly. Once IPsec is configured for OSPFv3, IPsec is invisible to you.
The secure socket API is used by applications to secure traffic. The API needs to allow the application to open, listen, and close secure sockets. The binding between the application and the secure socket layer also allows the secure socket layer to inform the application of changes to the socket, such as connection open and close events. The secure socket API is able to identify the socket; that is, it can identify the local and remote addresses, masks, ports, and protocol that carry the traffic requiring security.
Each interface has a secure socket state, which can be one of the following:
NULL: Do not create a secure socket for the interface if authentication is configured for the area.
DOWN: IPsec has been configured for the interface (or the area that contains the interface), but OSPFv3 either has not requested IPsec to create a secure socket for this interface, or there is an error condition.
GOING UP: OSPFv3 has requested a secure socket from IPsec and is waiting for a CRYPTO_SS_SOCKET_UP message from IPsec.
UP: OSPFv3 has received a CRYPTO_SS_SOCKET_UP message from IPsec.
CLOSING: The secure socket for the interface has been closed. A new socket may be opened for the interface, in which case the current secure socket makes the transition to the DOWN state. Otherwise, the interface will become UNCONFIGURED.
UNCONFIGURED: Authentication is not configured on the interface.
OSPFv3 will not send or accept packets while in the DOWN state.
For each virtual link, a master security information datablock is created for the virtual link. Because a secure socket must be opened on each interface, there will be a corresponding security information datablock for each interface in the transit area. The secure socket state is kept in the interface’s security information datablock. The state field in the master security information datablock shows the status of all of the secure sockets opened for the virtual link. If all of the secure sockets are UP, then the security state for the virtual link will be set to UP.
Packets sent on a virtual link with IPsec must use predetermined source and destination addresses. The first local area address found in the device’s intra-area-prefix LSA for the area is used as the source address. This source address is saved in the area data structure and used when secure sockets are opened and packets sent over the virtual link. The virtual link will not transition to the point-to-point state until a source address is selected. Also, when the source or destination address changes, the previous secure sockets must be closed and new secure sockets opened.
Virtual links are not supported for the IPv4 AF.
How to Configure OSPFv3 IPSec ESP Encryption and Authentication
Device# show ipv6 ospf interface
Ethernet0/0 is up, line protocol is up
Link Local Address 2001:0DB1:A8BB:CCFF:FE00:6E00, Interface ID 2
Area 0, Process ID 1, Instance ID 0, Router ID 10.10.10.1
Network Type BROADCAST, Cost:10
MD5 Authentication (Area) SPI 1000, secure socket state UP (errors:0)
Transmit Delay is 1 sec, State BDR, Priority 1
Designated Router (ID) 10.11.11.1, local address 2001:0DB1:A8BB:CCFF:FE00:6F00
Backup Designated router (ID) 10.10.10.1, local address
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:03
Index 1/1/1, flood queue length 0
Last flood scan length is 1, maximum is 1
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 10.11.11.1 (Designated Router)
Suppress hello for 0 neighbor(s)
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Feature Information for OSPFv3 IPSec ESP Encryption and Authentication
The following table
provides release information about the feature or features described in this
module. This table lists only the software release that introduced support for
a given feature in a given software release train. Unless noted otherwise,
subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform
support and Cisco software image support. To access Cisco Feature Navigator, go
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Table 1 Feature Information for OSPFv3 IPSec ESP Encryption and Authentication
OSPFv3 IPSec ESP Encryption and Authentication
IPv6 ESP extension headers can be used to provide authentication and confidentiality to OSPFv3.
The following commands were introduced or modified:
area virtual-link authentication,
ipv6 ospf area,
ipv6 ospf encryption,
show ipv6 ospf interface,
show ospfv3 interface.