diff --git a/synapse/api/auth.py b/synapse/api/auth.py
index 65ee1452c..f7cf17e43 100644
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@@ -20,7 +20,7 @@ from twisted.internet import defer
 from synapse.api.constants import EventTypes, Membership, JoinRules
 from synapse.api.errors import AuthError, Codes, SynapseError
 from synapse.util.logutils import log_function
-from synapse.types import UserID
+from synapse.types import EventID, RoomID, UserID
 
 import logging
 
@@ -65,6 +65,15 @@ class Auth(object):
                 # FIXME
                 return True
 
+            creating_domain = RoomID.from_string(event.room_id).domain
+            originating_domain = EventID.from_string(event.event_id).domain
+            if creating_domain != originating_domain:
+                if not self.can_federate(event, auth_events):
+                    raise SynapseError(
+                        403,
+                        "This room has been marked as unfederatable."
+                    )
+
             # FIXME: Temp hack
             if event.type == EventTypes.Aliases:
                 return True
@@ -153,6 +162,11 @@ class Auth(object):
                 user_id, room_id, repr(member)
             ))
 
+    def can_federate(self, event, auth_events):
+        creation_event = auth_events.get((EventTypes.Create, ""))
+
+        return creation_event.content.get("m.federate", True) is True
+
     @log_function
     def is_membership_change_allowed(self, event, auth_events):
         membership = event.content["membership"]
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index c5d1001b5..4f8ad824b 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -150,12 +150,15 @@ class RoomCreationHandler(BaseHandler):
         for val in raw_initial_state:
             initial_state[(val["type"], val.get("state_key", ""))] = val["content"]
 
+        creation_content = config.get("creation_content", {})
+
         user = UserID.from_string(user_id)
         creation_events = self._create_events_for_new_room(
             user, room_id,
             preset_config=preset_config,
             invite_list=invite_list,
             initial_state=initial_state,
+            creation_content=creation_content,
         )
 
         msg_handler = self.hs.get_handlers().message_handler
@@ -203,7 +206,7 @@ class RoomCreationHandler(BaseHandler):
         defer.returnValue(result)
 
     def _create_events_for_new_room(self, creator, room_id, preset_config,
-                                    invite_list, initial_state):
+                                    invite_list, initial_state, creation_content):
         config = RoomCreationHandler.PRESETS_DICT[preset_config]
 
         creator_id = creator.to_string()
@@ -225,9 +228,10 @@ class RoomCreationHandler(BaseHandler):
 
             return e
 
+        creation_content.update({"creator": creator.to_string()})
         creation_event = create(
             etype=EventTypes.Create,
-            content={"creator": creator.to_string()},
+            content=creation_content,
         )
 
         join_event = create(