Cisco ASA 5505 Configuration Manual page 462

Customizing Multicast Routing
Configuring the Designated Router Priority
The DR is responsible for sending PIM register, join, and prune messaged to the RP. When there is more
than one multicast router on a network segment, there is an election process to select the DR based on
DR priority. If multiple devices have the same DR priority, then the device with the highest IP address
becomes the DR.
By default, the adaptive security appliance has a DR priority of 1. To change this value, perform the
following steps:
In the main ASDM window, choose Configuration > Device Setup > Routing > Multicast > PIM >
Step 1
Protocol.
Choose the interface you want to enable for PIM from the table on the Protocol pane, and click Edit.
Step 2
The Edit PIM Protocol dialog box appears.
In the DR Priority field type the value for the designated router priority for the selected interface. The
Step 3
router with the highest DR priority on subnet becomes the designated router. Valid values range from 0
to 4294967294. The default DR priority is 1. Setting this value to 0 makes the adaptive security appliance
interface ineligible to become the default router.
Step 4 Click OK.
Configuring and Filtering PIM Register Messages
When the adaptive security appliance is acting as an RP, you can restrict specific multicast sources from
registering with it. This prevents unauthorized sources from registering with the RP. The Request Filter
pane lets you define the multicast sources from which the adaptive security appliance will accept PIM
register messages.
To filter PIM register messages, perform the following steps:
In the main ASDM window, choose Configuration > Device Setup > Routing > Multicast > PIM >
Step 1
Request Filter.
Step 2 Click Add.
The Request Filter Entry dialog box lets you define the multicast sources that are allowed to register with
the adaptive security appliance when the adaptive security appliance acts as an RP. You create the filter
rules based on the source IP address and the destination multicast address.
From the Action drop-down list, choose Permit to create a rule that allows the specified source of the
Step 3
specified multicast traffic to register with the adaptive security appliance, or choose Deny to create a
rule that prevents the specified source of the specified multicast traffic from registering with the adaptive
security appliance.
In the Source IP Address field, type the IP address for the source of the register message.
Step 4
In the Source Netmask field, type or choose the network mask from the drop-down list for the source of
Step 5
the register message.
In the Destination IP Address field, type the multicast destination address.
Step 6
In the Destination Netmask field, type or choose the network mask from the drop-down list for the
Step 7
multicast destination address.
Cisco ASA 5500 Series Configuration Guide using ASDM
24-12
Chapter 24 Configuring Multicast Routing
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