ADR 0168: a converged machine is filtered by the mesh alone, and the host says what else refuses (group 7)

Designs 08 and 05 revised; 141 resolved by ADR 0140 and 084 by ADR 0102 and
issue 128, both by reading; 143 and 144 decided, built on the matching
branches in mesh-host and mesh-controller, resolved when the home server's
record names the predecessor's chain.

03-DESIGN/01-to-be/08-connectivity.md

@@ -9,6 +9,7 @@ code:
   - mesh-host internal/apply (the service that reflects a rule set)
 updated: 2026-10-02
 decisions:
+  - 02-DECISIONS/0168-a-converged-machine-is-filtered-by-the-mesh-alone.md
   - 02-DECISIONS/0167-a-membership-carries-what-its-module-receives-and-who-the-mesh-is.md
   - 02-DECISIONS/0148-the-meshs-names-are-resolved-not-copied-into-containers.md
   - 02-DECISIONS/0151-a-routes-internal-name-is-composed-under-the-node-that-serves-it.md
@@ -710,6 +711,38 @@ needs no new filter; a declared port is reachable from off the private network a
 not; no address of a machine's own networks appears in a rendered filter, asserted on the text; and a
 machine reporting no outward link is refused in the control plane with its existing filter left alone.
 
+### A converged machine is filtered by the mesh alone, and the host says what else refuses
+
+*2026-10-02, [ADR 0168](../../02-DECISIONS/0168-a-converged-machine-is-filtered-by-the-mesh-alone.md),
+from [issues 143](../../04-ISSUES/143-converging-does-not-retire-the-firewall-it-found/00-report.md) and
+[144](../../04-ISSUES/144-the-predecessors-rules-outlive-the-firewall-it-was-found-as/00-report.md).*
+
+Retiring the found firewall was a step the flip took once, and said it had taken whatever happened;
+on the first machine with one it did not take, and a hand's work fifty minutes later was recorded as
+the mesh's. And "the firewall found" named one front end while a predecessor's chain in the container
+runtime's user hook — legacy iptables on one machine, invisible to a reader of nftables — filtered the
+forwarded path, refused ports the mesh declared open, and carried an allowance every module reaching
+another by the machine's own name relied on.
+
+**Convergence is a state the host keeps.** Every converged apply reads whether the found firewall is in
+force; enabled again, it is retired again and said; the record says whether the mesh disabled it or
+found it inactive, and a skipped step is said. **The host reports what filters the machine**, every
+apply, adopted or converged: every table and legacy chain that refuses, with an owner — the mesh's,
+the found firewall's, the runtime's own plumbing, a ban, or *other*, which is where the runtime's user
+chain's refusals go. **The mesh says which:** `node show` lists them; `status` names a converged machine
+anything *other* filters and is not well; the converge preview lists what filters the machine and the
+fate of each — retired with the front end, left as the runtime's, left as a ban, or *left in force and
+not the mesh's*. The mesh removes none of it; adoption's threshold does not move.
+
+*How it is checked:* host tests over rulesets captured from three machines of this mesh classify every
+refusing chain (a predecessor's chain in the legacy filter as *other*, a ban list reached through the
+user chain as a ban, a leftover front-end chain as *other*); a fake front end enabled again on a
+converged machine is retired again and said, found inactive is recorded as found; the report carries
+the filters and the found firewall's state and a change in them is worth an unasked report; controller
+tests over a fixture report check the recording, the preview's fates, the status JSON and the well
+predicate. Live: the home server's record names the predecessor's chain as *other* and `status`
+names the machine until the chain is removed by hand.
+
 ## 5 — Certificates
 
 **Two authorities, kept separate on purpose.**