For 1) you should also make sure you don't have an IP address on the vlan. For 2) changing the lookup key is the best approach, indeed. Several options are opened to you that depend on your traffic type. Going (*,G) might help, or not. In a pure L2 environment I would consider the mac mode or the mixed one. Check user guide for guidances and limitations. What is your platform? In a peak usage, what sh iproute reserved-entries stat returns?