Does it matter what method of NLB i am using , unicast or multicast ? the method i am using is multicast but the mac address i am getting from the cluster is unicast : 03bf.ac13.20c9 . I have a 6509 as a layer2 switch and nexus 7k is the gateway.Thanks .
Cisco Nexus Windows Nlb Multicast
I'm dealing with the following situation: I have 2 servers running window 2012 R2 and 1 server running windows 2008 R2. I need to build a Microsoff Network LoadBalancer Cluster using the 3 servers; servers are connected to a cisco Nexus Switch; servers are using Intel as well as Broadcom Nic cards. The servers are in the same subnet and the Network LoadBalancer VIP of the newly formed cluster is also in the same subnet. As long as wireshark is running on the servers the cluster is working (setting the nic interfaces to promiscuous mode) - members are detecting / seeing each other and passing each other the Primary / Master role when configured via the Network Load Balancer UI. How can this be possible ? Another strange thing: if I take one of the member offline from the cluster and run a wireshark capture, I can see the Microsoft Network Load Balancer hearthbeat broadcast messages being received from that host; nevertheless, as soon as I add the host again in the cluster, and I restart Wireshark, then the Network Load balancer cluster is working but in the Wireshark capture I don't see any Network Load Balancer hearthbeat messages received any longer .... Moreover, each time I take any host offline from the Network Load Balancer cluster or add it to the Network Load Balancer cluster, wireshark stops the formerly ongoing capture and displays a notification message stating that the ongoing capture cannot continue as the NIC formerly in use is no longer available ....
Thank you for your feedback. The NLB is operating in Multicast mode - the nexus has been configured to operate in IGMP multicast mode Unfortunately I don't have access to the nexus config to post it here .... Nevertheless, I'm puzzled by the fact that, in one scenario (server not part of the NLB cluster / group), running wireshark on the server I can see the hearthbeat messages .... as soon as I add the server to the NLB group, cluster intra-connectivity will not work until I start wireshark on the newly added server (setting in this way the NIC to promiscuous mode) ... nevertheless the wireshark capture now running on the newly added server doesn't show any hearthbear packets any longer ...
2# well - the switch whereto these dell blade-boxes are connected are two identical cisco nexus switches - there are two pass-through network modules on these blade-cabinets which is connected to the first and second nexus switch to have a fully redundant setup - and the switches act as one large switch becauserthey are interconnected with a vPC (virtual port-channel- which lets nexus switches merge together) and an inspecton of the mac adresse table looked fine (and remember that even though these nexus switches are pretty expensiv boxes they are "just" simple L2 switches so they don't participate in the arp process)I tried to see if it could be related to this by shutting the interface to one of the switches but no difference.
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