Microsoft NLB on HP switches

[RJ Gray]

I have a problem with the Microsoft Network Load Balancing (Multicast)  on windows server 2008. We are using the load balancing for our Exchange SMTP, and we keep getting disconnects and time outs. I have been told that this is due to the switch not retaining the MAC address for the NLB IP address, requiring it to be a static ARP. I have had a look about and can not find any way of adding the static ARP to our core routing switch (5308xl) or any other switch that we currently operate (our newest would be a 2810).

The one exchange server was configured with Multicast NLB on a network card with the network address 10.50.20.34/16 and 10.50.25.2/16 , while the other has the network address 10.50.20.35/16 and 10.50.25.2/16

All other network cards within the servers are disabled.

Is there any way to configure static MAC address entries into the 5308? or if anyone has any other suggestions this would be greatly appreciated.

[Mohammed Faiz]

Hi,

I'm afraid the option to add static ARP entries doesn't exist on the 5308 series switches. The ability to support multicast arp ranges was added in the later versions of the K15 code which runs on the 3500/6600/5400/8200 series  switches.

[Carsick0]

You can do this using a separate VLAN just for the NLB servers. You also need another switch. You connect all of your NLB servers to this new switch but don't worry about static ARPs. Your core switch up from this new switch only knows that the IP addresses or MAC addresses are on the downlink to the new switch so forwards all packets out of that interface. The new switch does not know where the specific machines are, so forwards the packets on all ports.

Therefore any NLB server on this new switch will see the packets and handle them accordingly. These, forward all ports packets, will not go back up to the core switch as it knows that is where they came from, so it keeps it all local.

It is not a pretty solution, but it does work. We have been using it for several years quite happily. Contact me if you need any further details or clarification.

Carrick

[ISoliman]

Use the latest K15 version since there is an enhancement that allows the switch to auto add the multicast mac address to the MAC table, this will interoperate with Microsoft NLB and should work fine after that (according to HP, check the release notes for more info they mentioned that in details)

[dcampregher]

HI,

I have 02 7506 in IRF stack and 03 clusters NLB in 03 vlans. All vlan interfaces are created in the core IRF, the servers or switches when the NLB servers are working, are conected in the Core and in the other 03 5120 switches.

NLB not work fine in my topoloy. I need keep the redundancy and works fine with NLB.

Any sugestion ?