All the addresses from the range are used, not just those
that are in use on the host.
https://bugzilla.redhat.com/show_bug.cgi?id=
1079917
<p><span class="since">Since 1.0.3</span> it is possible to
specify a public IPv4 address and port range to be used for
the NAT by using the <code><nat></code> subelement.
+ Note that all addresses from the range are used, not just those
+ that are in use on the host.
The address range is set with the <code><address></code>
subelements and <code>start</code> and <code>stop</code>
attributes: