https://blog.margrop.net/en/tag/dockhand/ Recent content in Dockhand on Margrop Blog Hugo -- gohugo.io en-US Mon, 13 Apr 2026 08:00:00 +0800 https://blog.margrop.net/en/post/docker-network-subnet-conflict-migration-record/ Mon, 13 Apr 2026 08:00:00 +0800 https://blog.margrop.net/en/post/docker-network-subnet-conflict-migration-record/ <p>This post records a very practical Docker networking failure: the number of containers kept growing, Docker&rsquo;s auto-assigned user-defined bridge networks eventually started landing in <code>192.168.x.x</code>, and those networks began colliding with the real home LAN. The symptoms were not dramatic at first. Nothing looked “broken” in the usual sense. Containers were still running, the host was still alive, and the dashboard still looked normal. But parts of the home network became unreliable, and once I dug into it on my NAS, the root cause turned out to be the Docker network allocation strategy rather than any single bad container.</p> <p>The fix was straightforward in principle, but important in practice: I moved Docker&rsquo;s automatic network pool to <code>172.16.0.0/12</code>, migrated the existing <code>192.168.*</code> networks onto the 172 private range, and made sure future networks created through Portainer, Dockhand, or plain <code>docker compose</code> would follow the same rule.</p>