Amazon, Verizon found using IPv4 240/4 addresses

&gt; Moreover, we did not find any 240&#x2F;4 prefix in the official prefix list shared by Amazon<p>Yeah, so about that:<p><a href="https:&#x2F;&#x2F;github.com&#x2F;seligman&#x2F;aws-ip-ranges&#x2F;commit&#x2F;2e0d9d87d4f5f39d741ff72adbec3a95e12880b7" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;seligman&#x2F;aws-ip-ranges&#x2F;commit&#x2F;2e0d9d87d4f...</a><p>They did briefly list 252.0.0.0&#x2F;10 in their published list of IP ranges. The people I spoke with about this at the time either claimed it was a mistake, or the state of the world that I should get used to (it broke some surprisingly fragile scripts on my side for silly reasons).<p>Given they removed it from their list of IPs 27 hours later, I&#x27;m guessing I wasn&#x27;t the only person freaking out. But yeah, they use it internally, and it leaks from time to time in surprising ways.

By the way, &quot;found using&quot; might sound like someone is angry at the companies for doing this, but the article doesn&#x27;t criticize them. Some people do find it objectionable, but my focus would be on accelerating <i>coordination</i> about the use of 240&#x2F;4 addresses, so people can agree on what behavior to expect.<p>(I&#x27;m the first author of a current draft about that, <a href="https:&#x2F;&#x2F;datatracker.ietf.org&#x2F;doc&#x2F;draft-schoen-intarea-unicast-240&#x2F;" rel="nofollow">https:&#x2F;&#x2F;datatracker.ietf.org&#x2F;doc&#x2F;draft-schoen-intarea-unicas...</a>, and I contributed to this RIPE Labs article but didn&#x27;t do the underlying research.)

This seems like a rather long post for the equivalent of &quot;haha, I can see your underpants.&quot; What&#x27;s the real significance to this vs seeing 10&#x2F;8 show up in a traceroute?

I know multiple large companies that would have no choice but to block any public use of these, as they have databases where these addresses have special meaning.<p>Yes, obviously that was a terrible choice to make. But it&#x27;s there. And legal compliance means they can&#x27;t just let these addresses in as normal unicast.<p>So while these can work as rfc1918 and similar, nobody will ever want to use these on publicly facing clients or servers. Too many places will never support them.<p>I&#x27;d rather be behind 3 layers of CGNAT.

I guess the big companies are not really keen to move to IPv6, since they control large swaths of IPv4 territory anyway. And only they would have the power to initiate a move, so i guess we are stuck in somewhat of a limbo here…?

<i>In sum, we only found two companies that are using 240&#x2F;4 IP space privately.</i><p>If anything, this is almost a warning from ARIN that this block might be finally repurposed. They find no one using it except for two companies internally ; they&#x27;re seeking to see if 240&#x2F;reserved is used or not is seems.<p>And really, anyone using 240 is to blame if it does get repurposed, so it seems like a good idea.

255.255.255.255 is the broadcast address and all other 240&#x2F;4 are &quot;for research purposes.&quot; IPv4 doesn&#x27;t need &quot;research&quot; anymore because it&#x27;s as dead as a whale oil barrel patch kit. I say fine: use them and un-bogon them. And then also deprecate the IPv4 internet by Dec 31, 2029.<p>Can&#x27;t migrate to IPv6 without having a real deadline.<p>That&#x27;s how it has to be because adoption that&#x27;s optional never happens: look at the US and metrication.

For it to be visible at BGP level I suppose they must be used publicly? But that aside, as a a bad practice, surely you can basically use <i>any</i> IP that you&#x27;re not supposed to, as long as you don&#x27;t care that it stops the real one being reachable? I.e. &#x27;reserved for future use&#x27; can be considered &#x27;private use if you must, for now, may change without notice&#x27;?

Couple points:<p>a. Do linux&#x2F;windows just take it 240&#x2F;4 address without special attention?<p>b. Fun time when 240&#x2F;4 will be released to public in the future it&#x27;s gonna be a huge headache for them.

&gt; many people wonder why there is still a market for IPv4<p>This is so tone deaf.<p>Put it this way, if Verizon, Google, and Facebook weren’t the champions for IPV6 for rolling it out, I’d be on board.<p>First and foremost: ipv6 is unnecessary for the end user, ipv4 provides the default assumption that a casual anonymizing NAT is in use.<p>And we can be real: SRV records, SNI, NAT work just fine and solved all the problems IPV6 went to solve _from the consumer perspective _.<p>I know this comment will be incredibly unpopular on HN, but the points need to be addressed. Your ISP is not your friend and neither are these other companies that sell your information without your explicit consent.

can someone explain what this means :p sorry