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NLB traffic getting flooded (IGMP mode in place). IGMP snooping table is properly populated, i.e. show ip igmp snooping groups --> we'll see the interested receivers/ports listed ('x', 'y') port 'x' port 'y' Ports 'a', 'b' and 'c' are UP and assigned to the same VLAN as port 'x' & port 'y'. They are also getting the NLB traffic (flooding). NLB packet structure (this is an example): **valid unicast src/dst IPs** src_ip = 1.1.1.1 dst_ip = 1.1.1.5 (NLB VIP) **valid unicast mac address but multicast destination mac address** src_mac = cafe.cafe.cafe dst_mac = 0100.5exx.xxxx ----> MULTICAST MAC ADDRESS Proper mrouter port/igmp querier is programmed in the Cat9K switch.
Cat9K running 16.x.x or 17.x.x code. NLB IGMP mode in use (this is a setting on the NLB server)
Configure a static MAC address entry listing the ports that should get this NLB traffic, i.e. mac address-table static 0100.5exx.xxxx vlan interface TenGigabitEthernet x/x/x
This is considered an expected behavior due to: For IGMP snooping, the Cat9K does not use MAC address for forwarding, it uses multicast IP address. New platforms are using this to avoid the overlapping addresses.
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