Comment 0 for bug 1697334

repo
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1. net with a subnet '10.0.0.0/26'
2. specify a IP address(10.0.0.10) in 'allowed_address_pairs' fields to create a port with the net. called Port1
3. specify the same IP address(10.0.0.10) in 'fixed_ip' fields to create another port with the net. called Port2
4. launch VMs with both of the ports. Port1 -- VM1 Port2 -- VM2.

Now VM1 and VM2 will use the same IP address(10.0.0.10) to access the external enviroment, VM2 is OK, but VM1 is not.
Just an example, if we set interface in a router, the default gateway of this subnet is 10.0.0.1. We can find the '10.0.0.10' ARP entry of the router namespace is VM2's port. So VM2 ping gateway is OK, but VM1 not. And the packets on gateway port'qr-XXXXX' we can see. All the Ping request packets which use 10.0.0.10 as Src ip from VM1 are accepted, but the qrouter namespace will send the Ping resp to VM2. I don't think this is a valid case.