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VM's with MS NLB (Network Load Balance) lost its connectivity


VM's with MS NLB (Network Load Balance) lost its connectivity

Hi All,



Our client has HP C7000 Enclosure with 6 x BL620c G7 Server Blade installed with VMware ESXi 5.5.
Interconnect module is 2 x HP VIRTUAL CONNECT FLEX-10/10D configured as Active/Active with 2 Shared Uplink Sets.
Other interconnect module is BROCADE 8/12C SAN SWITCH FOR BLADESYSTEM C-CLASS which is used as connectivity to HP SAN Switch and HP 3Par.

All VM's data are residing on the 3Par Storage.Virtual Connect Firmware is 4.10.
All VM's are working fine except for the vm's that has NLB (Network Load Balance).
VM's with NLB lost their network connectivity.

Maybe i miss something on the Flex10d settings.
Any idea on how to solve this issue?



Occasional Contributor

Re: VM's with MS NLB (Network Load Balance) lost its connectivity

I think it has more to do with NLB than with your Flex setup. You can configure the MS NLB with multicast or unicast and I think you have your default ESX settings which will not allow for promiscuous mode. Therefor your MAC adresses will be in trouble with multicast NLB.


We had more or less the same issues with MS NLB and we had to manually associate the NLB IP address with the generated MAC address in our firewall (or coreswitch, whereever it needs to be). Also we had to setup the cluster in Unicast mode instead of multicast mode.