diff --git a/weed/command/volume.go b/weed/command/volume.go
index 91b95cd33..73dc0ec80 100644
--- a/weed/command/volume.go
+++ b/weed/command/volume.go
@@ -347,6 +347,7 @@ func (v VolumeServerOptions) startVolumeServer(volumeFolders, maxVolumeCounts, v
 		// volume server. One identity truth across VS, block service, control
 		// bridge, and runtime ownership.
 		blockService.SetServerID(volumeServerId)
+		blockService.SetAdvertisedIP(*v.ip) // CP13-2: routable IP, not opaque ID
 		volumeServer.SetBlockService(blockService)
 	}
 
diff --git a/weed/server/qa_block_soak_test.go b/weed/server/qa_block_soak_test.go
index b1df0e659..dcec41653 100644
--- a/weed/server/qa_block_soak_test.go
+++ b/weed/server/qa_block_soak_test.go
@@ -84,6 +84,7 @@ func newSoakSetup(t *testing.T) *soakSetup {
 		blockDir:       filepath.Join(dir, "vs1_9333"),
 		listenAddr:     "127.0.0.1:3260",
 		localServerID:  "vs1:9333",
+		advertisedIP:   "127.0.0.1",
 		v2Bridge:       v2bridge.NewControlBridge(),
 		v2Orchestrator: engine.NewRecoveryOrchestrator(),
 		replStates:     make(map[string]*volReplState),
diff --git a/weed/server/volume_server_block.go b/weed/server/volume_server_block.go
index 870083248..3aa8a5820 100644
--- a/weed/server/volume_server_block.go
+++ b/weed/server/volume_server_block.go
@@ -59,9 +59,14 @@ type BlockService struct {
 	lastAssignMu sync.RWMutex
 	lastAssign   map[string]lastAppliedAssignment
 	// localServerID: stable identity for this volume server.
-	// INTERIM: uses listenAddr (transport-shaped). Should be replaced
-	// with a registry-assigned stable server ID in a later hardening pass.
+	// May be an opaque string (from -id flag) or ip:port (default fallback).
+	// NOT guaranteed to be a routable address — do not use for transport endpoints.
 	localServerID string
+
+	// advertisedIP: routable IP for this volume server (from -ip flag or auto-detected).
+	// Used by CP13-2 to canonicalize wildcard-bind replica listener addresses to
+	// routable ip:port. This is always a real IP, never an opaque identity string.
+	advertisedIP string
 }
 
 // V2Orchestrator returns the V2 engine orchestrator for inspection/testing.
@@ -70,12 +75,18 @@ func (bs *BlockService) V2Orchestrator() *engine.RecoveryOrchestrator {
 }
 
 // SetServerID sets the stable server identity for V2 control semantics.
-// Should be called with the gRPC address that the master knows this VS by,
-// replacing the interim listenAddr-based identity.
+// This may be an opaque string (from -id flag) — not guaranteed routable.
 func (bs *BlockService) SetServerID(id string) {
 	bs.localServerID = id
 }
 
+// SetAdvertisedIP sets the routable IP for replica endpoint canonicalization.
+// This must be a real IP address (from -ip flag or auto-detected), never an
+// opaque server identity. Called at startup from volume.go.
+func (bs *BlockService) SetAdvertisedIP(ip string) {
+	bs.advertisedIP = ip
+}
+
 // WireStateChangeNotify sets up shipper state change callbacks on all
 // registered volumes so that degradation/recovery triggers an immediate
 // heartbeat via the provided channel. Non-blocking send (buffered chan 1).
@@ -525,16 +536,19 @@ func (bs *BlockService) setupPrimaryReplicationMulti(path string, addrs []blockv
 
 // setupReplicaReceiver starts the replica WAL receiver.
 func (bs *BlockService) setupReplicaReceiver(path, dataAddr, ctrlAddr string) {
-	// CP13-2: Pass the canonical host from localServerID so wildcard-bind
-	// listeners resolve to the authoritative routable IP, not outbound-IP fallback.
-	advertisedHost := bs.localServerID
-	if idx := strings.LastIndex(advertisedHost, ":"); idx >= 0 {
-		advertisedHost = advertisedHost[:idx]
-	}
+	// CP13-2: Pass the routable advertisedIP (from -ip flag, NOT from -id/serverID)
+	// so wildcard-bind listeners resolve to a real IP, not an opaque identity string.
 	var canonDataAddr, canonCtrlAddr string
+	advIP := bs.advertisedIP
 	if err := bs.blockStore.WithVolume(path, func(vol *blockvol.BlockVol) error {
-		if err := vol.StartReplicaReceiver(dataAddr, ctrlAddr, advertisedHost); err != nil {
-			return err
+		if advIP != "" {
+			if err := vol.StartReplicaReceiver(dataAddr, ctrlAddr, advIP); err != nil {
+				return err
+			}
+		} else {
+			if err := vol.StartReplicaReceiver(dataAddr, ctrlAddr); err != nil {
+				return err
+			}
 		}
 		// Read back canonical addresses from the receiver.
 		if vol.ReplicaReceiverAddr() != nil {
diff --git a/weed/storage/blockvol/sync_all_bug_test.go b/weed/storage/blockvol/sync_all_bug_test.go
index 184da06b7..372b7bdc1 100644
--- a/weed/storage/blockvol/sync_all_bug_test.go
+++ b/weed/storage/blockvol/sync_all_bug_test.go
@@ -104,6 +104,29 @@ func TestBug3_ReplicaAddr_MustBeIPPort_WildcardBind(t *testing.T) {
 			t.Fatalf("CtrlAddr %q does not use advertisedHost 10.0.0.99", info.CtrlAddr)
 		}
 	})
+
+	// Case 4: opaque non-IP advertisedHost must NOT produce a usable routable address.
+	// CP13-2: this proves that passing an opaque server identity (e.g., from -id flag)
+	// as the advertised host would produce a non-routable address. The production path
+	// uses advertisedIP (from -ip flag), not localServerID, to prevent this.
+	t.Run("opaque_identity_not_routable", func(t *testing.T) {
+		vol3 := createTestVol(t)
+		defer vol3.Close()
+		// Pass an opaque identity string — NOT an IP address.
+		if err := vol3.StartReplicaReceiver(":0", ":0", "my-custom-server-id"); err != nil {
+			t.Fatal(err)
+		}
+		info := vol3.ReplicaReceiverAddr()
+		if info == nil {
+			t.Fatal("ReplicaReceiverAddr() returned nil")
+		}
+		// The address will be "my-custom-server-id:port" — NOT parseable as a routable IP.
+		ip := net.ParseIP(strings.Split(info.DataAddr, ":")[0])
+		if ip != nil {
+			t.Fatalf("opaque identity should NOT produce a parseable IP, got %s", info.DataAddr)
+		}
+		t.Logf("correctly non-routable: %s (production uses advertisedIP, not serverID)", info.DataAddr)
+	})
 }
 
 // --- Bug 2: LSN gap after shipper degradation ---