&gt; ... in the same &#x2F;64 range for the most part, so as easy to block&#x2F;filter&#x2F;limit as one IPv4 address.<p>Possibly even easier, because of IPv4 deaggregation.<p>(Because of IPv4 address scarcity, many providers have discontinous IPv4 address space. This is mostly a problem for the core, because it leads to much larger BGP routing tables.)