Comment 1 for bug 1720734

Long option is discussed here: https://etherpad.openstack.org/p/DF-AAP

The immediate proposed solution is:

Add a configuration option to dnat app. The option tells dnat to NAT according to IP and not port. This means that the dnat flows translate the IP address (as done today), possibly sets the OVS metadata register, clears reg6 and reg7, and then passes the packet to the router.

The drawback is that the internal network must now be connected to the router. This requirement shouldn't exist for public network. (May require modification for l3 network).