diff --git a/meshchatx/src/backend/identity_context.py b/meshchatx/src/backend/identity_context.py
index 2407fe4..f2f5cce 100644
--- a/meshchatx/src/backend/identity_context.py
+++ b/meshchatx/src/backend/identity_context.py
@@ -217,6 +217,14 @@ class IdentityContext:
 
         # Register LXMF delivery identity
         inbound_stamp_cost = self.config.lxmf_inbound_stamp_cost.get()
+        # Enforce max stamp cost when block strangers is enabled on startup
+        if (
+            self.config.block_all_from_strangers.get()
+            and isinstance(inbound_stamp_cost, int)
+            and inbound_stamp_cost < 254
+        ):
+            inbound_stamp_cost = 254
+            self.config.lxmf_inbound_stamp_cost.set(254)
         self.local_lxmf_destination = self.message_router.register_delivery_identity(
             identity=self.identity,
             display_name=self.config.display_name.get(),
@@ -413,6 +421,18 @@ class IdentityContext:
         thread.daemon = True
         thread.start()
 
+        # start background thread for LXMF flood protection cooldown
+        thread = threading.Thread(
+            target=asyncio.run,
+            args=(
+                self.app.lxmf_flood_protection_cooldown_loop(
+                    self.session_id, context=self
+                ),
+            ),
+        )
+        thread.daemon = True
+        thread.start()
+
         # start background thread for auto propagation node selection
         thread = threading.Thread(
             target=asyncio.run,