The journal container could not reach v6-only fediverse instances
(e.g. social.ullrich.is) because the compose project network was
IPv4-only. The flagship host has working IPv6, and Docker >= 27
auto-allocates a ULA subnet with NAT66 masquerading when a network
sets enable_ipv6, so the fix is a one-line opt-in per network.
Applying it to an existing deployment requires recreating the
network (docker compose down && up -d) — a brief full-stack
restart on the flagship and the persistent staging project.
PR-preview networks are created fresh per PR and need nothing.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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