Problem with MIcrosoft NLB

[Stefano Colombo]

A customer of ours has an HP 9305 switch.
We have configured two windows 2003 servers in NLB.
The problem is that after a while , typically less than 5 minutes , it stops working correctly. It happens that some user can connect and some not.

NLB is configured in unicast.
Searching in the MS KB we found that the hosts should be connected to Layer2 switch ( or hub ) only .
For Layer3 switch is recommended to make Layer2 VLANs

Does anyone have had the same problem with this class of switch ?

Any help greatly appreciated
Stefano