Some more documentation in the blog post

Signed-off-by: Jacob Kiers <jacob@jacobkiers.net>

Corefile

@@ -0,0 +1,7 @@
+hod.experiments.jacobkiers.net.:53 {
+    log
+    auto hod.experiments.jacobkiers.net. {
+	directory /etc/coredns/zones/
+        reload 10s
+    }
+}

content/posts/2021-08-17-serving-blog-content-over-dns.md

@@ -1,12 +1,16 @@
 +++
-title = Serving blog content over DNS
+title = HTML over DNS: Serving Blog Content Over DNS
 date = 2021-08-15
 author = Jacob Kiers
 +++
 
+## What's up?
+
 You might not be able to see it immediately, but the content of this page is verved over DNS.
 
-This works because of the new DNS-over-HTTP support, which, at least at Cloudflare, also has an API.
+This works because of [DNS over HTTPS] for which there is an [API from Cloudflare].
+
+## How it works
 
 That API is used to load the contents of this page, essentially like this:
 
@@ -14,6 +18,50 @@ That API is used to load the contents of this page, essentially like this:
 fetch("https://cloudflare-dns.com/dns-query?ct=application/dns-json&type=TXT&name=post.hod.experiments.jacobkiers.net");
 ```
 
-Please see the [source code] for the details of how it works.
+The content itself is served over DNS, using CoreDNS, with these contents:
 
-[source code]: https://github.com/jacobkiers/html-over-dns
+```
+hod.experiments.jacobkiers.net.:53 {
+    log
+    auto hod.experiments.jacobkiers.net. {
+	directory /etc/coredns/zones/
+        reload 10s
+    }
+}
+```
+
+This feeds into a zone file, which looks like this:
+
+```bind
+$TTL 5m	; Default TTL
+@	IN	SOA	experiments.jacobkiers.net.	postmaster.jacobkiers.net. (
+	2021081612	; serial
+	1h		; slave refresh interval
+	15m		; slave retry interval
+	1w		; slave copy expire time
+	1h		; NXDOMAIN cache time
+	)
+
+$ORIGIN hod.experiments.jacobkiers.net.
+
+;
+; domain name servers
+;
+@	IN	NS  experiments.jacobkiers.net.
+
+
+;; START BLOG RECORDS
+; posts-2021-08-17-serving-blog-content-over-dns-md
+posts-2021-08-17-serving-blog-content-over-dns-md	60	IN	TXT	"t=text/markdown;c=3;h=2fd63f0f408ad1336283999d0487ced9;m=eyJ0aXRsZSI6IlNlcnZpbmcgYmxvZyBjb250ZW50IG92ZXIgRE5TIiwiZGF0ZSI6IjIwMjEtMDgtMTUiLCJhdXRob3IiOiJKYWNvYiBLaWVycyJ9"
+0.2fd63f0f408ad1336283999d0487ced9	60	IN	TXT	"WW91IG1pZ2h0IG5vdCBiZSBhYmxlIHRvIHNlZSBpdCBpbW1lZGlhdGVseSwgYnV0IHRoZSBjb250ZW50IG9mIHRoaXMgcGFnZSBpcyB2ZXJ2ZWQgb3ZlciBETlMuCgpUaGlzIHdvcmtzIGJlY2F1c2Ugb2YgdGhlIG5ldyBETlMtb3Zlci1IVFRQIHN1cHBvcnQsIHdoaWNoLCBhdCBsZWFzdCBhdCBDbG91ZGZsYXJlLCBhbHNvIGhhcy"
+1.2fd63f0f408ad1336283999d0487ced9	60	IN	TXT	"BhbiBBUEkuCgpUaGF0IEFQSSBpcyB1c2VkIHRvIGxvYWQgdGhlIGNvbnRlbnRzIG9mIHRoaXMgcGFnZSwgZXNzZW50aWFsbHkgbGlrZSB0aGlzOgoKYGBganMKZmV0Y2goImh0dHBzOi8vY2xvdWRmbGFyZS1kbnMuY29tL2Rucy1xdWVyeT9jdD1hcHBsaWNhdGlvbi9kbnMtanNvbiZ0eXBlPVRYVCZuYW1lPXBvc3QuaG9kLmV4cGVy"
+2.2fd63f0f408ad1336283999d0487ced9	60	IN	TXT	"aW1lbnRzLmphY29ia2llcnMubmV0Iik7CmBgYAoKUGxlYXNlIHNlZSB0aGUgW3NvdXJjZSBjb2RlXSBmb3IgdGhlIGRldGFpbHMgb2YgaG93IGl0IHdvcmtzLgoKW3NvdXJjZSBjb2RlXTogaHR0cHM6Ly9naXRodWIuY29tL2phY29ia2llcnMvaHRtbC1vdmVyLWRucwo="
+```
+
+These records are base64 encoded content, so when concatenated and decoded, they give the content of the posts.
+
+Please see the [source code] for the details.
+
+[source code]: https://github.com/jacobkiers/html-over-dns "Yes, the title is a pun..."
+[DNS over HTTPS]: https://en.wikipedia.org/wiki/DNS_over_HTTPS
+[API from Cloudflare]: https://developers.cloudflare.com/1.1.1.1/dns-over-https/json-format