here i configure static host route for every client, the net traffic will be routed to diff interface even they are in the same subnet.
>Instead, if you make eth1 as 192.168.x+1.z/24 then this will guarantee automatic routing is always >correct for the test because subnet is different.
I know that, good idea.  but in our test env. the guest ip assigned by dhcp server, they are in the same subnet, so i add static route to resolve this issue.