pool: handle host+port collision between inbound and outbound.

lib/net/pool.js

@@ -510,6 +510,14 @@ Pool.prototype._handleLeech = function _handleLeech(socket) {
     return;
   }
 
+  // Some kind of weird port collision
+  // between inbound ports and outbound ports.
+  if (this.peers.get(addr)) {
+    this.logger.debug('Port collision (%s).', hostname);
+    socket.destroy();
+    return;
+  }
+
   this.addLeech(socket);
 };