&gt; It is a long article listing all the differences - my original question was why did they decide to make all those changes instead of just expanding the address space. All of the changes except for the change to the size of the address space bother me.<p>What specific changes? Give me your top 3.<p>&gt; Did you setup your work network for IPv6 or did someone else do it?<p>My work network isn&#x27;t set up for IPv6, that&#x27;s where I had the problem.<p>&gt; My original question was about what justified an obvious problematic change that is celebrating 20 years with only a 10% adoption.<p>What makes you think an address-space-only change would have been less &quot;problematic&quot; or more rapidly adopted? Because as far as I can tell there&#x27;s no significant difference between &quot;just expanding the address space&quot; and IPv6.