Multicast的話看這一條
Possible Cause
If you are using multicast support, you might find that your router has difficulty resolving the primary IP address into a multicast media access control (MAC) address using the ARP protocol.
Solution
To check this, verify that you can use ping to access the cluster from a client on the cluster's subnet and to access the cluster hosts' dedicated IP addresses from a computer outside the router. If these tests work properly, the
router is probably at fault. You should be able to add a static ARP entry to the router to circumvent the problem. You can also turn off Network Load Balancing multicast support and use a unicast network address without a hub.
還有這一條
Possible Cause
When using Network Load Balancing in either multicast or unicast mode, routers need to be able to accept proxy ARP responses (IP-to-network address mappings that are received with a different network source address in the Ethernet frame).
Solution
Make sure that your router has proxy ARP support turned on. You can also set a static ARP entry to keep proxy ARP support disabled in the router.
都是要在路由器上對ARP進行相關設置, 例如自建一條對應Multicast mac address的ARP紀錄
邊幫助, 邊鍛鍊
