295
• Collects C-RP information from the received advertisement messages from the C-RPs.
• Encapsulates the C-RP information in the RP-set information.
• Distributes the RP-set information to all routers in the IPv6 PIM-SM domain.
All routers use the same hash algorithm to get an RP for a specific IPv6 multicast group.
Configuring a legal BSR address range enables filtering of BSMs based on the address range which
prevents a maliciously configured host from masquerading as a BSR. The same configuration must be
made on all routers in the IPv6 PIM-SM domain. The following describes the typical BSR spoofing cases
and the corresponding preventive measures:
• Some maliciously configured hosts can forge BSMs to fool routers and change RP mappings. Such
attacks often occur on border routers. A BSR is inside the network and hosts are outside the network.
To protect a BSR against external attacks, you can enable the border routers to do the following:
{ Perform neighbor checks and RPF checks on BSMs.
{ Discard unwanted messages.
• When an attacker controls a router on the network, the attacker can configure the router as a C-BSR
to win the BSR election. Through this router, the attacker controls the advertising of RP information.
For security purposes, you can configure a legal BSR address range on all routers on the network.
All routers will discard BSMs that are out of the legal address range.
These preventive measures can partially protect the BSR in a network. However, if an attacker controls a
legal BSR, the problem still exists.
When you configure a C-BSR, reserve a relatively large bandwidth between the C-BSR and the other
devices in the IPv6 PIM-SM domain.
To configure a C-BSR:
Ste
Command
Remarks
1. Enter system view.
system-view
N/A
2. Enter IPv6 PIM view.
ipv6 pim [ vpn-instance
vpn-instance-name ]
N/A
3. Configure a C-BSR.
c-bsr ipv6-address [ scope
scope-id ] [ hash-length
hash-length | priority priority ] *
By default, no C-BSR is configured.
4. (Optional.) Configure a legal
BSR address range.
bsr-policy acl6-number
By default, no restrictions are
defined.
Configuring an IPv6 PIM domain border
As the administrative core of an IPv6 PIM-SM domain, the BSR sends the collected RP-set information in
the BSMs to all routers in the IPv6 PIM-SM domain.
An IPv6 PIM domain border is a bootstrap message boundary. Each BSR has its specific service scope.
IPv6 PIM domain border interfaces partition a network into different IPv6 PIM-SM domains. Bootstrap
messages cannot cross a domain border in either direction.
Perform the following configuration on routers that you want to configure as an IPv6 PIM domain border.
To configure an IPv6 PIM border domain:
To Next Page
Loading...
