diff --git a/src/main/java/net/schmizz/sshj/SSHClient.java b/src/main/java/net/schmizz/sshj/SSHClient.java
index 22343258..3fb8cfd1 100644
--- a/src/main/java/net/schmizz/sshj/SSHClient.java
+++ b/src/main/java/net/schmizz/sshj/SSHClient.java
@@ -362,7 +362,6 @@ public class SSHClient
     @Override
     public void disconnect()
             throws IOException {
-        assert isConnected();
         trans.disconnect();
         super.disconnect();
         assert !isConnected();
diff --git a/src/main/java/net/schmizz/sshj/transport/TransportImpl.java b/src/main/java/net/schmizz/sshj/transport/TransportImpl.java
index 054ce034..7e67710b 100644
--- a/src/main/java/net/schmizz/sshj/transport/TransportImpl.java
+++ b/src/main/java/net/schmizz/sshj/transport/TransportImpl.java
@@ -381,9 +381,9 @@ public final class TransportImpl
     public void disconnect(DisconnectReason reason, String message) {
         close.lock();
         try {
-            disconnectListener.notifyDisconnect(reason);
-            getService().notifyError(new TransportException(reason, "Disconnected"));
             if (!close.isSet()) {
+                disconnectListener.notifyDisconnect(reason);
+                getService().notifyError(new TransportException(reason, "Disconnected"));
                 sendDisconnect(reason, message);
                 finishOff();
                 close.set();