Cisco Systems 3750E Advertising Network 0.0.0.0 to Dvmrp Neighbors, Ip dvmrp accept-filter, 42-42

Chapter 42 Configuring IP Multicast Routing

Configuring Basic DVMRP Interoperability Features

	Command	Purpose
Step 9
	ip dvmrp accept-filter	Configure an acceptance filter for incoming DVMRP reports.
	access-list-number [distance]	By default, all destination reports are accepted with a distance of 0.
	neighbor-listaccess-list-number
		Reports from all neighbors are accepted.
		• For access-list-number, specify the access list number created in
		Step 2. Any sources that match the access list are stored in the
		DVMRP routing table with distance.
		• (Optional) For distance, enter the administrative distance to the
		destination. By default, the administrative distance for DVMRP
		routes is 0 and take precedence over unicast routing table routes. If
		you have two paths to a source, one through unicast routing (using
		PIM as the multicast routing protocol) and another using DVMRP,
		and if you want to use the PIM path, increase the administrative
		distance for DVMRP routes. The range is 1 to 255.
		• For neighbor-listaccess-list-number, enter the number of the
		neighbor list created in Step 2. DVMRP reports are accepted only by
		those neighbors on the list.
Step 10
	end	Return to privileged EXEC mode.
Step 11
	show running-config	Verify your entries.
Step 12
	copy running-config startup-config	(Optional) Save your entries in the configuration file.

To disable the filter, use the no ip dvmrp accept-filter access-list-number[distance] neighbor-list access-list-numberinterface configuration command.

This example shows how to configure a DVMRP tunnel. In this configuration, the IP address of the tunnel on the Cisco switch is assigned unnumbered, which causes the tunnel to appear to have the same IP address as port 1. The tunnel endpoint source address is 172.16.2.1, and the tunnel endpoint address of the remote DVMRP router to which the tunnel is connected is 192.168.1.10. Any packets sent through the tunnel are encapsulated in an outer IP header. The Cisco switch is configured to accept incoming DVMRP reports with a distance of 100 from 198.92.37.0 through 198.92.37.255.

Switch(config)# ip	multicast-routing
Switch(config)# interface		tunnel 0
Switch(config-if)#	ip unnumbered gigabitethernet1/0/1
Switch(config-if)#	ip pim	dense-mode
Switch(config-if)#	tunnel	source gigabitethernet1/0/1
Switch(config-if)#	tunnel	destination 192.168.1.10
Switch(config-if)#	tunnel	mode dvmrp
Switch(config-if)#	ip dvmrp accept-filter 1 100
Switch(config-if)#	interface gigabitethernet1/0/1
Switch(config-if)#	ip address 172.16.2.1 255.255.255.0
Switch(config-if)#	ip pim	dense-mode

Switch(config)# exit

Switch(config)# access-list 1 permit 198.92.37.0 0.0.0.255

Advertising Network 0.0.0.0 to DVMRP Neighbors

If your switch is a neighbor of an mrouted Version 3.6 device, you can configure the software to advertise network 0.0.0.0 (the default route) to the DVMRP neighbor. The DVMRP default route computes the RPF information for any multicast sources that do not match a more specific route.

Do not advertise the DVMRP default into the MBONE.

	Catalyst 3750-E and 3560-E Switch Software Configuration Guide
42-42	OL-9775-02