diff --git a/libp2p/pubsub/gossipsub.py b/libp2p/pubsub/gossipsub.py
index 43602a29..9f26865c 100644
--- a/libp2p/pubsub/gossipsub.py
+++ b/libp2p/pubsub/gossipsub.py
@@ -354,10 +354,11 @@ class GossipSub(IPubsubRouter, Service):
         topic_in_fanout: bool = topic in self.fanout
         fanout_peers: set[ID] = set()
 
-        for peer in self.fanout[topic]:
-            if self._check_back_off(peer, topic):
-                continue
-            fanout_peers.add(peer)
+        if topic_in_fanout:
+            for peer in self.fanout[topic]:
+                if self._check_back_off(peer, topic):
+                    continue
+                fanout_peers.add(peer)
 
         fanout_size = len(fanout_peers)
         if not topic_in_fanout or (topic_in_fanout and fanout_size < self.degree):
diff --git a/libp2p/tools/constants.py b/libp2p/tools/constants.py
index a9ba4b76..f7d367e7 100644
--- a/libp2p/tools/constants.py
+++ b/libp2p/tools/constants.py
@@ -26,6 +26,7 @@ LISTEN_MADDR = multiaddr.Multiaddr("/ip4/127.0.0.1/tcp/0")
 
 FLOODSUB_PROTOCOL_ID = floodsub.PROTOCOL_ID
 GOSSIPSUB_PROTOCOL_ID = gossipsub.PROTOCOL_ID
+GOSSIPSUB_PROTOCOL_ID_V1 = gossipsub.PROTOCOL_ID_V11
 
 
 class GossipsubParams(NamedTuple):
@@ -40,6 +41,10 @@ class GossipsubParams(NamedTuple):
     heartbeat_interval: float = 0.5
     direct_connect_initial_delay: float = 0.1
     direct_connect_interval: int = 300
+    do_px: bool = False
+    px_peers_count: int = 16
+    prune_back_off: int = 60
+    unsubscribe_back_off: int = 10
 
 
 GOSSIPSUB_PARAMS = GossipsubParams()
diff --git a/tests/utils/factories.py b/tests/utils/factories.py
index 4df82033..1beac861 100644
--- a/tests/utils/factories.py
+++ b/tests/utils/factories.py
@@ -443,6 +443,10 @@ class GossipsubFactory(factory.Factory):
     heartbeat_interval = GOSSIPSUB_PARAMS.heartbeat_interval
     direct_connect_initial_delay = GOSSIPSUB_PARAMS.direct_connect_initial_delay
     direct_connect_interval = GOSSIPSUB_PARAMS.direct_connect_interval
+    do_px = GOSSIPSUB_PARAMS.do_px
+    px_peers_count = GOSSIPSUB_PARAMS.px_peers_count
+    prune_back_off = GOSSIPSUB_PARAMS.prune_back_off
+    unsubscribe_back_off = GOSSIPSUB_PARAMS.unsubscribe_back_off
 
 
 class PubsubFactory(factory.Factory):
@@ -568,6 +572,10 @@ class PubsubFactory(factory.Factory):
         heartbeat_initial_delay: float = GOSSIPSUB_PARAMS.heartbeat_initial_delay,
         direct_connect_initial_delay: float = GOSSIPSUB_PARAMS.direct_connect_initial_delay,  # noqa: E501
         direct_connect_interval: int = GOSSIPSUB_PARAMS.direct_connect_interval,
+        do_px: bool = GOSSIPSUB_PARAMS.do_px,
+        px_peers_count: int = GOSSIPSUB_PARAMS.px_peers_count,
+        prune_back_off: int = GOSSIPSUB_PARAMS.prune_back_off,
+        unsubscribe_back_off: int = GOSSIPSUB_PARAMS.unsubscribe_back_off,
         security_protocol: TProtocol | None = None,
         muxer_opt: TMuxerOptions | None = None,
         msg_id_constructor: None
@@ -588,6 +596,10 @@ class PubsubFactory(factory.Factory):
                 heartbeat_interval=heartbeat_interval,
                 direct_connect_initial_delay=direct_connect_initial_delay,
                 direct_connect_interval=direct_connect_interval,
+                do_px=do_px,
+                px_peers_count=px_peers_count,
+                prune_back_off=prune_back_off,
+                unsubscribe_back_off=unsubscribe_back_off,
             )
         else:
             gossipsubs = GossipsubFactory.create_batch(
@@ -602,6 +614,10 @@ class PubsubFactory(factory.Factory):
                 heartbeat_initial_delay=heartbeat_initial_delay,
                 direct_connect_initial_delay=direct_connect_initial_delay,
                 direct_connect_interval=direct_connect_interval,
+                do_px=do_px,
+                px_peers_count=px_peers_count,
+                prune_back_off=prune_back_off,
+                unsubscribe_back_off=unsubscribe_back_off,
             )
 
         async with cls._create_batch_with_router(