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Cisco Catalyst Blade Switch 3130 and 3032 for Dell Software Configuration Guide
OL-13270-06
Chapter 45 Configuring IP Multicast Routing
Configuring IP Multicast Routing
Configuring DNS-Based SSM Mapping
To configure DNS-based SSM mapping, you need to create a DNS server zone or add records to an
existing zone. If the routers that are using DNS-based SSM mapping are also using DNS for other
purposes, you should use a normally configured DNS server. If DNS-based SSM mapping is the only
DNS implementation being used on the router, you can configure a false DNS setup with an empty root
zone or a root zone that points back to itself.
Beginning in privileged EXEC mode, follow these steps to configure DNS-based SSM mapping:
Configuring Static Traffic Forwarding with SSM Mapping
Use static traffic forwarding with SSM mapping to statically forward SSM traffic for certain groups.
Beginning in privileged EXEC mode, follow these steps to configure static traffic forwarding with SSM
mapping:
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
ip igmp ssm-map enable
Enable SSM mapping for groups in a configured SSM range.
Step 3
ip igmp ssm-map query dns
(Optional) Enable DNS-based SSM mapping.
By default, the
ip igmp ssm-map
command enables DNS-based SSM
mapping. Only the
no
form of this command is saved to the running
configuration.
Note
Use this command to re-enable DNS-based SSM mapping if
DNS-based SSM mapping is disabled.
Step 4
ip domain multicast
domain-prefix
(Optional) Change the domain prefix used by the switch for DNS-based
SSM mapping.
By default, the switch uses the
ip-addr.arpa
domain prefix.
Step 5
ip name-server
server-address1
[
server-address2... server-address6
]
Specify the address of one or more name servers to use for name and
address resolution.
Step 6
Repeat Step 5 to configure additional
DNS servers for redundancy, if required.
—
Step 7
end
Return to privileged EXEC mode.
Step 8
show running-config
Verify your entries.
Step 9
copy running-config startup-config
(Optional) Save your entries in the configuration file.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface
type number
Select an interface on which to statically forward traffic for a multicast
group using SSM mapping, and enter interface configuration mode.
Note
Static forwarding of traffic with SSM mapping works with either
DNS-based SSM mapping or statically configured SSM
mapping.