this post was submitted on 11 Aug 2025
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I'm currently trying to install Docker on my old Raspberry Pi (3 Model B+) to host some personal projects. When I run docker run hello-world, I get:

Unable to find image 'hello-world:latest' locally
docker: Error response from daemon: Get "https://registry-1.docker.io/v2/library/hello-world/manifests/sha256:ec153840d1e635ac434fab5e377081f17e0e15afab27beb3f726c3265039cfff": dial tcp [2600:1f18:2148:bc00:eff:d3ae:b836:fa07]:443: connect: network is unreachable

My Internet connection does not support IPv6 at all, which would explain why this error occurs. But how do I force docker-pull to only use IPv4?

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[–] Zagorath@aussie.zone 1 points 10 months ago* (last edited 10 months ago) (1 children)
$ dig registry-1.docker.io

; <<>> DiG 9.18.33-1~deb12u2-Debian <<>> registry-1.docker.io
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 50801
;; flags: qr rd ra; QUERY: 1, ANSWER: 8, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;registry-1.docker.io.          IN      A

;; ANSWER SECTION:
registry-1.docker.io.   33      IN      A       54.210.249.78
registry-1.docker.io.   33      IN      A       44.218.153.24
registry-1.docker.io.   33      IN      A       107.20.112.188
registry-1.docker.io.   33      IN      A       34.234.222.10
registry-1.docker.io.   33      IN      A       34.195.83.243
registry-1.docker.io.   33      IN      A       52.21.128.203
registry-1.docker.io.   33      IN      A       52.0.248.137
registry-1.docker.io.   33      IN      A       52.207.69.161

;; Query time: 47 msec
;; SERVER: 192.168.20.1#53(192.168.20.1) (UDP)
;; WHEN: Tue Aug 12 22:27:45 AEST 2025
;; MSG SIZE  rcvd: 177
$ cat /etc/resolv.conf
# Generated by NetworkManager
search Home
nameserver 192.168.20.1

edit: oh, and in my router's configuration:

  • Primary DNS Server:9.9.9.9
  • Secondary DNS Server:1.1.1.1
[–] iglou@programming.dev 2 points 10 months ago (1 children)

Well this is getting weird.

Have you tried checking if your os has a resolution cashe active? If so, try to flush it.

[–] Zagorath@aussie.zone 1 points 10 months ago* (last edited 10 months ago) (1 children)

I never set one up myself, and this 11 year-old thread implies that Raspbian doesn't have one set up by default. It is a very old thread though, so could be wrong.

edit: this is more recent and also says Raspbian doesn't have DNS caching by default

[–] iglou@programming.dev 2 points 10 months ago (1 children)

At this point I am assuming that it is actually a docker issue.

Can you show your docker daemon configuration?

Hard to tell where it is on your machine. Try ~/.docker/daemon.json, or maybe /etc/docker/daemon.json... Else look for it haha

[–] Zagorath@aussie.zone 1 points 10 months ago

There's a ~/.docker/config.json. In that there're some auths, with keys https://index.docker.io/v1/, https://index.docker.io/v1/access-token, and https://index.docker.io/v1/refresh-token, and then there's "currentContext": "rootless".

There's ~/.docker/contexts/meta/[a long hex string]/meta.json, with {"Name":"rootless","Metadata":{"Description":"Rootless mode"},"Endpoints":{"docker":{"Host":"unix:///run/user/1000/docker.sock","SkipTLSVerify":false}}}.

The only file in /etc/docker is key.json.