Users Guide

ip igmp access-group access-list-name
Dell Networking OS Behavior: Do not enter the ip igmp access-group command before creating the access-list. If you do, after
entering your first deny rule, Dell Networking OS clears the multicast routing table and re-learns all groups, even those not covered by the
rules in the access-list, because there is an implicit deny all rule at the end of all access-lists. Therefore, configuring an IGMP join request
filter in this order might result in data loss. If you must enter the ip igmp access-group command before creating the access-list,
prevent Dell Networking OS from clearing the routing table by entering a permit any rule with a high sequence number before you enter
any other rules.
In the following example, virtual local area network (VLAN) 400 is configured with an access list to permit only IGMP reports for group
239.0.0.1. Though Receiver 2 sends a membership report for groups 239.0.0.1 and 239.0.0.2, a multicast routing table entry is created only
for group 239.0.0.1. VLAN 300 has no access list limiting Receiver 1, so both IGMP reports are accepted, and two corresponding entries
are created in the routing table.
Figure 87. Preventing a Host from Joining a Group
The following table lists the location and description shown in the previous illustration.
Table 46. Preventing a Host from Joining a Group — Description
Location Description
1/21
• Interface GigabitEthernet 1/21
• ip pim sparse-mode
448 Multicast Features