diff --git a/src/connections.rs b/src/connections.rs
index af8417a..56045cd 100644
--- a/src/connections.rs
+++ b/src/connections.rs
@@ -273,6 +273,14 @@ impl<T: std::fmt::Debug + Clone + Serialize + DeserializeOwned + Send + Sync + '
                                 ConnectionState::Closing(CloseReason::NotAcceptingConnections),
                             ),
                         );
+                    } else if self.config.identifier != identifier {
+                        self.connections.insert(
+                            *addr,
+                            Connection::from(
+                                *addr,
+                                ConnectionState::Closing(CloseReason::InvalidIdentifier),
+                            ),
+                        );
                     } else {
                         self.connections.insert(
                             *addr,
diff --git a/src/package.rs b/src/package.rs
index 7dab9db..8bcd375 100644
--- a/src/package.rs
+++ b/src/package.rs
@@ -17,6 +17,7 @@ pub enum CloseReason {
     ShuttingDown,
     /// Closed because local peer initiated close
     SelfClosed,
+    InvalidIdentifier,
 }
 
 impl std::fmt::Display for CloseReason {
@@ -27,6 +28,7 @@ impl std::fmt::Display for CloseReason {
             CloseReason::Error => write!(f, "Error"),
             CloseReason::ShuttingDown => write!(f, "Shutting down"),
             CloseReason::SelfClosed => write!(f, "Closed"),
+            CloseReason::InvalidIdentifier => write!(f, "Invalid Identifier"),
         }
     }
 }