Find useless NAT

[hknutzen]

When is a "bind_nat = x" useless?

1. bind_nat is applied to an unmanaged device and
2. the area where this bind_nat is applicable, has no managed device and
3. this bind_nat doesn't prevent an address conflict.

How do we check this?

1. is easy
2. needs to find the area bordered by other occurences of "bind_nat = x".
   If this area is located inside a single zone or zone_cluster, then there is no managed device.
3. we need to check all networks with nat:x and compare its address with all networks inside the bind_nat area. We can't always use the original address, but must check if some other NAT is applied.

This seems to be rather complex.