Multicast Snoop; Multicast Proxy - D-Link NetDefend DFL-210 User Manual

4.6.3. IGMP Configuration
IGMP Queries
Normally, both these types of rules has to be specified for IGMP to work. One exception to this is if
the multicast source is located on a network directly connected to the router. In this case, no query
rule is needed.
A second exception is if a neighboring router is statically configured to deliver a multicast stream to
the NetDefend Firewall. In this case also, an IGMP query would not have to be specified.
NetDefendOS supports two IGMP modes of operation - Snoop and Proxy.
Figure 4.11. Multicast Snoop
Figure 4.12. Multicast Proxy
to new multicast groups or change current multicast subscriptions.
Queries are IGMP messages sent from the router towards the hosts in order to
make sure that it will not close any stream that some host still wants to receive.
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Chapter 4. Routing