{"id":558,"date":"2025-11-29T09:40:00","date_gmt":"2025-11-28T23:40:00","guid":{"rendered":"https:\/\/www.ubermotive.com\/?p=558"},"modified":"2026-01-20T19:24:38","modified_gmt":"2026-01-20T09:24:38","slug":"no-nat-november-2025","status":"publish","type":"post","link":"https:\/\/www.ubermotive.com\/?p=558","title":{"rendered":"No NAT November 2025"},"content":{"rendered":"\n<p>No NAT November was a buzz-term a few years ago. I could only find a few blogs about it. I thought I&#8217;d try it myself this year, at least for a bit. I&#8217;ve already deployed all of the IPv6 transition tech I possibly could, and my home network covers a broad range of use cases.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Deployed transition technologies<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>IPv6 (RFC 8200): Obviously. I have a native \/48 subnet from my ISP.<\/li>\n\n\n\n<li>DNS64 (RFC 6147): BIND9 DNS implements the &#8220;dns64&#8221; option.<\/li>\n\n\n\n<li>NAT64  (RFC 6052): Installed jool and integrated it with netfilter.<\/li>\n\n\n\n<li>PREF64 (RFC 8781): Configured radvd with the &#8220;nat64prefix&#8221; option.<\/li>\n\n\n\n<li>IPv6-Only Preferred (RFC 8925): Set &#8220;v6-only-preferred&#8221; (option 108) flag in kea DHCPv4.<\/li>\n<\/ul>\n\n\n\n<p>After setting all of this up, the ultimate step is removing the &#8220;routers&#8221; option from DHCPv4, so that no route to the internet is advertised over IPv4. This is what I understand &#8220;no NAT&#8221; to mean. There is still a local IPv4 subnet. My server still has a public IPv4 address.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Observations<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>XBox Series X<\/strong>: Despite removing the &#8220;routers&#8221; DHCP option, it took it upon itself to assume that 192.168.1.1 was a router and did it anyway. It&#8217;s possibly a failsafe for misconfigured networks, but it still cheated.<\/li>\n\n\n\n<li><strong>Google Pixel<\/strong> (Android): These saw the v6-only-preferred DHCP flag and enabled CLAT. I did see one VoWifi bug which prevented most incoming calls. I narrowed it down to the UDP keepalive packets having no destination MAC address and being dropped. <a href=\"https:\/\/issuetracker.google.com\/issues\/381164175\">Google don&#8217;t care<\/a> though. <\/li>\n\n\n\n<li><strong>Android Printing<\/strong>: I can&#8217;t print using AirPrint because the Android Built-in Print Service (BIPS) is <a href=\"https:\/\/android.googlesource.com\/platform\/packages\/services\/BuiltInPrintService\/+\/refs\/heads\/main\/src\/com\/android\/bips\/discovery\/MdnsDiscovery.java#108\" data-type=\"link\" data-id=\"https:\/\/android.googlesource.com\/platform\/packages\/services\/BuiltInPrintService\/+\/refs\/heads\/main\/src\/com\/android\/bips\/discovery\/MdnsDiscovery.java#109\">hardcoded to discard IPv6 printers upon discovery<\/a>. I spent quite some time checking the configuration and monitoring network traffic only to find the words &#8220;Must be IPv4&#8221; in MdnsDiscovery.java.<\/li>\n\n\n\n<li><strong>Samsung Phone<\/strong> (Android): These enabled CLAT and worked fine.<\/li>\n\n\n\n<li><strong>Nintendo Switch<\/strong>: Had no internet connectivity whatsoever.<\/li>\n\n\n\n<li><strong>Steam<\/strong>: Would not log in. Even when the underlying OS had full IPv6 network capability (but not CLAT). The <a href=\"https:\/\/github.com\/ValveSoftware\/steam-for-linux\/issues\/3372\">bug was reported<\/a> 11 years ago has not been acknowledged by Valve.<\/li>\n\n\n\n<li><strong>Google Chromecast HD<\/strong>: My phone could not communicate with it when the phone was on CLAT. I suspect the Chromecast relies on IPv4 broadcast for discovery, and CLAT doesn&#8217;t really have a concept of subnets.<\/li>\n\n\n\n<li><strong>Ubuntu Linux<\/strong>: No issues at an OS level. I tried <a href=\"https:\/\/github.com\/toreanderson\/clatd\">clatd<\/a> to see how it was. It technically worked, but the integration was terrible. I had to manually start the service to get it working.<\/li>\n\n\n\n<li><strong>Microsoft Windows<\/strong>: It somewhat worked on my work computer, but I had issues where intellij wouldn&#8217;t communicate with github, despite git commands working directly from powershell.<\/li>\n\n\n\n<li><strong>LG washing machine<\/strong> (2020 model): No connectivity.<\/li>\n\n\n\n<li><strong>Rinnai air conditioner<\/strong> (2020 model with Midea wifi module): No connectivity.<\/li>\n\n\n\n<li><strong>Hisense VIDAA Smart TV<\/strong>: Works without any issues.<\/li>\n\n\n\n<li><strong>OzWeather Weather Station<\/strong>: No connectivity. There is now a huge gap in my Weather Underground data.<\/li>\n\n\n\n<li><strong>Apple iPad<\/strong>: I&#8217;ve heard they have great CLAT support. I haven&#8217;t turned it on yet. I hate Apple.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Next year?<\/h3>\n\n\n\n<p>Microsoft have a CLAT implementation that has just entered a <a href=\"https:\/\/techcommunity.microsoft.com\/blog\/networkingblog\/windows-clat-enters-private-preview-a-milestone-for-ipv6-adoption\/4459534\">private preview<\/a> in November 2025. By 2026, it may be a standard part of Windows. It&#8217;s nice to see them implementing a real OS feature instead of just monetising their user base.<\/p>\n\n\n\n<p><\/p>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>No NAT November was a buzz-term a few years ago. I could only find a few blogs about it. I thought I&#8217;d try it myself this year, at least for a bit. I&#8217;ve already deployed all of the IPv6 transition tech I possibly could, and my home network covers a broad range of use cases. [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-558","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/www.ubermotive.com\/index.php?rest_route=\/wp\/v2\/posts\/558","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ubermotive.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ubermotive.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ubermotive.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ubermotive.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=558"}],"version-history":[{"count":12,"href":"https:\/\/www.ubermotive.com\/index.php?rest_route=\/wp\/v2\/posts\/558\/revisions"}],"predecessor-version":[{"id":572,"href":"https:\/\/www.ubermotive.com\/index.php?rest_route=\/wp\/v2\/posts\/558\/revisions\/572"}],"wp:attachment":[{"href":"https:\/\/www.ubermotive.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=558"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ubermotive.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=558"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ubermotive.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=558"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}