diff --git a/Plugin/unraid/api/setup.php b/Plugin/unraid/api/setup.php
index 60ffc05..2d73ee3 100644
--- a/Plugin/unraid/api/setup.php
+++ b/Plugin/unraid/api/setup.php
@@ -397,6 +397,47 @@ if (!file_exists(CONF_DIR . '/' . $confFile)) {
     }
 }
 
+// ── Adopt the owner's custom docker networks ─────────────────────────────────────────────────
+// Sent by the wizard, which read them out of the owner's host conf that onboard Phase 1 cached
+// into the RAM conf dir. This is the one setup value a fresh mirror has no way to know: the
+// template ships NETWORK_CONNECT_NETWORKS with its only entry commented out, and the owner then
+// deploys containers here onto a network named in the *owner's* templates. An empty list is what
+// left twelve containers created against a network that did not exist.
+//
+// Outside the create block above, so it applies to a conf that already exists — the wizard is
+// re-runnable and a mirror rebuilt against an existing host conf needs this just as much.
+//
+// Merged, never replaced: anything already listed here was put there deliberately.
+$netsRaw = trim((string)($_POST['networks'] ?? ''));
+if ($netsRaw !== '' && $hostIdLow !== 'host1') {
+    // Written into a file that bash sources, so the name is validated rather than trusted.
+    // Docker's own charset for a network name is a superset of this; anything outside it is
+    // far more likely to be an injection attempt than a real network.
+    $nets = array_values(array_filter(
+        array_map('trim', explode(',', $netsRaw)),
+        fn($n) => $n !== ''
+               && preg_match('/^[A-Za-z0-9][A-Za-z0-9._-]{0,62}$/', $n)
+               && !preg_match('/^(bridge|host|none|br\d)/i', $n)
+    ));
+    if ($nets) {
+        $netVar = $hostId . '_NETWORK_CONNECT_NETWORKS';
+        vv_conf_edit($confFile, function (string $cur) use ($netVar, $nets): ?string {
+            $existing = vv_parse_conf_list($cur, $netVar);
+            $merged   = $existing;
+            foreach ($nets as $n) {
+                if (!in_array($n, $merged, true)) $merged[] = $n;
+            }
+            if ($merged === $existing) return null;   // already adopted — no write, no audit noise
+            $body = '';
+            foreach ($merged as $n) $body .= '        "' . $n . '"' . "\n";
+            $new = preg_replace(
+                '/^(\s*' . preg_quote($netVar, '/') . '\s*=\s*\()(.*?)(^\s*\))/ms',
+                "\$1\n" . $body . '$3', $cur, 1, $count);
+            return ($count === 1 && $new !== null) ? $new : null;
+        }, [], [$netVar]);
+    }
+}
+
 // Write setup state file — lets partner servers know HOST1 is configured.
 // Read-modify-write: vv_setup_state_write() replaces the file wholesale, and re-running the
 // wizard must not erase onboarding progress recorded by the partnership phases.
diff --git a/Plugin/unraid/include/config.php b/Plugin/unraid/include/config.php
index 50a8d5d..4fd0be9 100644
--- a/Plugin/unraid/include/config.php
+++ b/Plugin/unraid/include/config.php
@@ -883,6 +883,30 @@ function vv_parse_conf_scalar(string $raw, string $key): string {
     return vv_conf_unquote(ltrim($m[1]));
 }
 
+// Read a bash array of plain strings out of a conf, skipping commented entries.
+//
+// Distinct from vv_parse_conf_array() in scheduler.php, which looks the same but keeps only
+// entries ending in .sh — it exists to read job lists. Handing it a list of docker networks
+// returns an empty array, silently, because none of them are scripts. This one makes no
+// assumption about what the entries mean.
+//
+// The closing paren must be at the start of its own line, matching the shape conf_upgrade
+// writes and the same anchor the scheduler parser uses — a value containing ')' would
+// otherwise end the array early.
+function vv_parse_conf_list(string $raw, string $key): array {
+    if (!preg_match('/^\s*' . preg_quote($key, '/') . '\s*=\s*\((.*?)^\s*\)/ms', $raw, $m)) {
+        return [];
+    }
+    $out = [];
+    foreach (explode("\n", $m[1]) as $line) {
+        if (preg_match('/^\s*#/', $line)) continue;              // commented-out entry
+        if (!preg_match('/"([^"]*)"|\'([^\']*)\'/', $line, $e)) continue;
+        $val = trim($e[1] !== '' ? $e[1] : ($e[2] ?? ''));
+        if ($val !== '') $out[] = $val;
+    }
+    return $out;
+}
+
 // Unquote one bash word the way bash does, because the regexes this replaced did not and the
 // conf is read by both. Three separate regexes each handled one quoting style in isolation and
 // none of them handled an escape or two quoted runs in a row, so a value carrying a quote or a
diff --git a/Plugin/unraid/pages/setup.php b/Plugin/unraid/pages/setup.php
index 317be2d..dfb6afb 100644
--- a/Plugin/unraid/pages/setup.php
+++ b/Plugin/unraid/pages/setup.php
@@ -51,7 +51,7 @@ $detectedHostname = vv_get_hostname();
 // Matching is exact and case-insensitive, never a prefix: two hosts called Tower and Tower2 must
 // not resolve to each other, and there is no ambiguity to tolerate when the value was written by
 // the very host it names.
-$vvDetected = ['slot' => '', 'primary' => '', 'role' => ''];
+$vvDetected = ['slot' => '', 'primary' => '', 'role' => '', 'networks' => [], 'networks_src' => ''];
 $vvMasterRaw = vv_read_conf_raw('master.conf');
 if ($vvMasterRaw !== '' && $detectedHostname !== '') {
     preg_match_all('/^\s*(HOST\d+)\s*=\s*"([^"]*)"/m', $vvMasterRaw, $vvHm, PREG_SET_ORDER);
@@ -70,6 +70,34 @@ if ($vvMasterRaw !== '' && $detectedHostname !== '') {
     // The primary is whatever HOST1 says, and it is only useful to a host that is not HOST1.
     if ($vvDetected['role'] === 'partner') $vvDetected['primary'] = $vvSlots['host1'] ?? '';
 }
+
+// ── Custom docker networks, adopted from the owner ───────────────────────────────────────────
+// master.conf names the hosts; it does not name the networks, which live in each host's own
+// host*.conf. The owner's copy is available here anyway: onboard Phase 1 caches it into
+// VV_CONF_RAM_CACHE_DIR as soon as SSH works, before this node has finished setup.
+//
+// This is the value a fresh mirror cannot know and cannot be expected to type. host.conf.template
+// ships NETWORK_CONNECT_NETWORKS with its only entry commented out, so a mirror comes up with an
+// empty list while the owner deploys containers onto a network named in the owner's templates —
+// which is exactly how twelve containers ended up created against a network that did not exist.
+//
+// Adopting the owner's list also means docker_network_connect.sh will recreate the network here
+// after an Unraid update wipes it, which is the whole reason that script exists.
+if ($vvDetected['role'] === 'partner' && $vvDetected['slot'] !== '') {
+    $vvOwnerConf = VV_CONF_RAM_CACHE_DIR . '/host1.conf';
+    if (is_readable($vvOwnerConf)) {
+        $vvOwnerRaw = (string)@file_get_contents($vvOwnerConf);
+        $vvNets = vv_parse_conf_list($vvOwnerRaw, 'HOST1_NETWORK_CONNECT_NETWORKS');
+        // br* is ipvlan/macvlan tied to the owner's own hardware — its parent interface does not
+        // transfer, and adopting the name would attach this host's containers to the wrong thing.
+        $vvNets = array_values(array_filter($vvNets, fn($n) =>
+            $n !== '' && !preg_match('/^(bridge|host|none|br\d)/i', $n)));
+        if ($vvNets) {
+            $vvDetected['networks']     = $vvNets;
+            $vvDetected['networks_src'] = basename($vvOwnerConf);
+        }
+    }
+}
 ?>
 <link rel="stylesheet" href="/plugins/varaverk/css/varaverk.css">
 <style>
@@ -333,6 +361,18 @@ function vvApplyDetectedIdentity() {
         + `${d.primary}. Change anything below if that is wrong.`
       : 'Identity read from master.conf — this server is HOST1, the primary.';
     banner.appendChild(note);
+
+    // Named separately from identity: this one is adopted from the owner's cached host conf,
+    // not from master.conf, and it is the value the operator would otherwise have to know.
+    if (Array.isArray(d.networks) && d.networks.length) {
+      const nets = document.createElement('div');
+      nets.style.cssText = 'margin-top:6px;padding:7px 10px;border-radius:3px;background:#0d1a28;'
+                         + 'border:1px solid #1a3a5a;color:#7ab;font-size:11px;line-height:1.5;';
+      nets.textContent = `Custom network${d.networks.length > 1 ? 's' : ''} adopted from `
+                       + `${d.primary || 'the primary'}: ${d.networks.join(', ')} — added to this `
+                       + `server's conf on save, so the containers it deploys here have somewhere to land.`;
+      banner.appendChild(nets);
+    }
   }
 }
 
@@ -549,9 +589,13 @@ function vvDoSave() {
     if (mySlot === 'host2') host2 = hostname;
   }
   vvSetBtn('Saving…', true);
+  // Networks come from the owner's cached conf, not from any field — there is nothing for the
+  // operator to type and nothing to get wrong. Empty on the primary, and on a partner whose
+  // owner conf has not been cached yet; the save handler treats absent as "nothing to adopt".
+  const networks = (vvDetectedIdentity?.networks ?? []).join(',');
   fetch('/plugins/varaverk/api/setup.php', {
     method: 'POST', headers: {'Content-Type': 'application/x-www-form-urlencoded'},
-    body: new URLSearchParams({action:'save', host1, host2, my_slot:mySlot, my_hostname:hostname, storage_mode:_vvStorageMode})
+    body: new URLSearchParams({action:'save', host1, host2, my_slot:mySlot, my_hostname:hostname, storage_mode:_vvStorageMode, networks})
   }).then(r => r.json()).then(d => {
     if (d.ok) {
       if (d.needs_migration) {