d this way are
       <code class="literal">172.20.143.89/32</code> for a single host, or
       <code class="literal">172.20.143.0/24</code> for a small network, or
       <code class="literal">10.6.0.0/16</code> for a larger one.
       An IPv6 address range might look like <code class="literal">::1/128</code>
       for a single host (in this case the IPv6 loopback address) or
       <code class="literal">fe80::7a31:c1ff:0000:0000/96</code> for a small
       network.
       <code class="literal">0.0.0.0