3com 5500 + NLB multcast igmp

[Wain]

Hi,

I have 3 terminalserver with multicast igmp nlb. The terminalservers are connected to 3 ports on the 3com 5500.

My problem ist that if a client want to connect to the virtual ip adress there is no connection. If I undo arp check on 3com switch the virtual ip adress is available and the clients can open a connection. If I now check the arp table there is a dynamic arp entry with the virtual IP adress to one switch port. If a client connects to the virtual ip adress now - the client connects only to the terminalserver which port is in the arp table. So I have no network load balancing. How can I configure the swich correctly?

Thank you for you help,

Oliver