bind nginx proxy manager to the tailscale address

It was the only service here publishing on 0.0.0.0, and a published docker port
is not behind the firewall: docker writes its DNAT rules straight into the nat
table, which ufw's INPUT chain never sees. `ufw default deny incoming` never
covered 80/443/81 — ufw-docker-rules.conf on the host exists to patch exactly
that, and patching a rule is weaker than never opening the socket.

The address is read from `tailscale ip -4` at run time rather than passed in,
because the host provisioning has already done `tailscale up` by the time this
executes. It is validated against 100.64.0.0/10, the range tailscale and
headscale both allocate from. SETUP_NPM_BIND overrides it.

With neither, selecting NPM exits instead of falling back to 0.0.0.0 — a
fallback would silently undo the point of the change.

Two consequences worth knowing. tailscaled becomes a boot-order dependency, so
the script warns when it is not enabled at boot; docker's restart policy covers
the window but only if the tailnet comes up on its own. And HTTP-01 ACME
challenges can no longer reach port 80, so any certificate NPM issues now needs
DNS-01.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

scripts/setup/setup-dockers.sh

@@ -10,6 +10,8 @@
 # Environment overrides:
 #   SETUP_DOCKER_SERVICES="1 2 3"  — pre-select services (or "all"/"none")
 #   SETUP_DOCKER_NETWORK="services" — docker network name
+#   SETUP_NPM_BIND="100.64.0.8"     — host address Nginx Proxy Manager publishes on. Defaults to this
+#                                     node's Tailscale IPv4; set it explicitly to bind somewhere else.
 
 set -e
 
@@ -47,6 +49,44 @@ prompt_value() {
 # ─── docker network ─────────────────────────────────────────────────────────
 DOCKER_NETWORK="${SETUP_DOCKER_NETWORK:-services}"
 
+# ─── Nginx Proxy Manager bind address ───────────────────────────────────────
+#
+# NPM is the only service here that ever published on 0.0.0.0, and a published Docker port is not
+# behind the firewall: Docker writes its DNAT rules directly into the nat table, which UFW's INPUT
+# chain never sees. `ufw default deny incoming` does not cover 80/443/81 — that is what the host's
+# ufw-docker-rules.conf exists to patch, and patching a rule is weaker than never opening the socket.
+#
+# So bind to the tailnet address instead. The kernel then refuses the socket on every other interface
+# and the firewall stops being load-bearing for this. The address is read at run time rather than
+# passed in, because by the time this script runs the host provisioning has already done `tailscale up`.
+resolve_npm_bind() {
+  if [[ -n "${SETUP_NPM_BIND:-}" ]]; then
+    echo "$SETUP_NPM_BIND"
+    return
+  fi
+  local ip
+  ip=$(tailscale ip -4 2>/dev/null | head -1)
+  # 100.64.0.0/10 — the CGNAT range both Tailscale and Headscale allocate from. Anything outside it
+  # means `tailscale ip` answered with something unexpected, and a bind address is not a value to
+  # guess at: the whole point is that it is NOT reachable from the internet.
+  if [[ "$ip" =~ ^100\.(6[4-9]|[7-9][0-9]|1[01][0-9]|12[0-7])\. ]]; then
+    echo "$ip"
+    return
+  fi
+  echo ""
+}
+
+NPM_BIND="$(resolve_npm_bind)"
+
+# Binding to an address that belongs to another service's interface makes that service a boot-order
+# dependency: if tailscaled has not brought tailscale0 up yet, the container cannot get its socket and
+# Docker falls back on the restart policy to retry. That converges, but only if the tailnet comes up
+# at all on its own.
+if [[ -n "$NPM_BIND" ]] && ! systemctl is-enabled --quiet tailscaled 2>/dev/null; then
+  warn "tailscaled is not enabled at boot — NPM binds $NPM_BIND, which will not exist after a reboot"
+  warn "until the tailnet is up. Fix with: sudo systemctl enable tailscaled"
+fi
+
 # Ensure network exists
 if ! docker network inspect "$DOCKER_NETWORK" &>/dev/null; then
   docker network create "$DOCKER_NETWORK" >/dev/null 2>&1
@@ -94,6 +134,14 @@ MAILHOG_SELECTED=false
 for svc in $SERVICES; do
   case "$svc" in
     1)
+      if [[ -z "$NPM_BIND" ]]; then
+        fail "Nginx Proxy Manager selected, but no Tailscale IPv4 was found on this host."
+        echo "  Bring the tailnet up first (the host provisioning does this), or choose the" >&2
+        echo "  address deliberately:  SETUP_NPM_BIND=<ip> bash scripts/setup/setup-dockers.sh" >&2
+        echo "  Publishing it on 0.0.0.0 is not offered — Docker bypasses UFW, so that would put" >&2
+        echo "  80/443/81 on every interface the host has." >&2
+        exit 1
+      fi
       COMPOSE_SERVICES+=("nginx-proxy-manager")
       cat >> "$COMPOSE_DIR/docker-compose.yaml" <<SVC
   nginx-proxy-manager:
@@ -101,9 +149,9 @@ for svc in $SERVICES; do
     container_name: nginx-proxy-manager
     restart: unless-stopped
     ports:
-      - "80:80"
-      - "443:443"
-      - "81:81"
+      - "$NPM_BIND:80:80"
+      - "$NPM_BIND:443:443"
+      - "$NPM_BIND:81:81"
     volumes:
       - ./npm_data:/data
       - ./npm_letsencrypt:/etc/letsencrypt
@@ -238,6 +286,10 @@ fi
 # ─── output parseable values to stdout ───────────────────────────────────────
 echo "COMPOSE_DIR=$COMPOSE_DIR"
 
+if [[ " ${COMPOSE_SERVICES[*]} " == *" nginx-proxy-manager "* ]]; then
+  echo "NPM_BIND=$NPM_BIND"
+fi
+
 if [[ -n "$PG_PASSWORD" ]]; then
   echo "POSTGRES_URL=postgresql://postgres:${PG_PASSWORD}@127.0.0.1:5432/${PG_DATABASE}"
 fi