General discussion • Docker intermittently uses IPv6 despite disabling IPv6 system-wide on Raspberry Pi

Hi everyone,

I'm running Docker on a Raspberry Pi 4 (8GB model) with Raspberry Pi OS, and I’m facing an issue where Docker intermittently attempts to use IPv6 addresses to connect to Docker Hub, even though I've disabled IPv6 both system-wide and within Docker's configuration. Below are the steps I’ve taken so far to enforce IPv4 usage and disable IPv6:

System Configuration:

IPv6 Disabled at Kernel Level:
- I modified to include :
- Verified with , which shows no IPv6 addresses.

Docker Daemon Configuration:
- Edited to disable IPv6 and set IPv4 DNS servers: Docker Service Environment Overrides:
- Created override file with the following settings:
- Reloaded and restarted Docker using: NetworkManager Configuration:
- Configured with:
- Restarted NetworkManager: iptables Rules to Block IPv6:
- Set up rules to drop all IPv6 traffic:
- Saved rules using .

The Issue:
Despite all these configurations, Docker still sometimes attempts to resolve registry URLs using IPv6, resulting in errors like: Additional Observations:
- The first attempt to pull an image after a restart often succeeds, but subsequent attempts fail.
- I have verified that IPv6 is not assigned to any network interfaces ( shows only IPv4 addresses).
- Entries in map Docker registry domains to known IPv4 addresses.

My Question:
What else could be causing Docker to intermittently use IPv6 despite these configurations? Are there any Docker-specific or system-level settings that I might have overlooked that could force IPv4 consistently? Any insights or suggestions would be greatly appreciated!

Thanks in advance!

Statistics: Posted by fsl4faisal — Fri Sep 13, 2024 3:31 am

---