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Author SHA1 Message Date
Jacob Kiers
d09aedbb8c Some more documentation in the blog post 
Signed-off-by: Jacob Kiers <jacob@jacobkiers.net>
 2021-08-17 09:32:33 +02:00
2 changed files with 59 additions and 4 deletions
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Corefile Normal file
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@ -0,0 +1,7 @@
hod.experiments.jacobkiers.net.:53 {
log
auto hod.experiments.jacobkiers.net. {
directory /etc/coredns/zones/
reload 10s
}
}

56
content/posts/2021-08-17-serving-blog-content-over-dns.md
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@ -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
```hcl
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