diff --git a/src/add-ons/kernel/network/protocols/tcp/TCPEndpoint.cpp b/src/add-ons/kernel/network/protocols/tcp/TCPEndpoint.cpp
index b0da601fe6..dc3a4a19fa 100644
--- a/src/add-ons/kernel/network/protocols/tcp/TCPEndpoint.cpp
+++ b/src/add-ons/kernel/network/protocols/tcp/TCPEndpoint.cpp
@@ -728,18 +728,20 @@ TCPEndpoint::Listen(int count)
 
 	MutexLocker _(fLock);
 
-	if (fState != CLOSED)
+	if (fState != CLOSED && fState != LISTEN)
 		return B_BAD_VALUE;
 
-	fAcceptSemaphore = create_sem(0, "tcp accept");
-	if (fAcceptSemaphore < B_OK)
-		return ENOBUFS;
-
-	status_t status = fManager->SetPassive(this);
-	if (status != B_OK) {
-		delete_sem(fAcceptSemaphore);
-		fAcceptSemaphore = -1;
-		return status;
+	if (fState == CLOSED) {
+		fAcceptSemaphore = create_sem(0, "tcp accept");
+		if (fAcceptSemaphore < B_OK)
+			return ENOBUFS;
+	
+		status_t status = fManager->SetPassive(this);
+		if (status != B_OK) {
+			delete_sem(fAcceptSemaphore);
+			fAcceptSemaphore = -1;
+			return status;
+		}
 	}
 
 	gSocketModule->set_max_backlog(socket, count);
diff --git a/src/add-ons/kernel/network/protocols/unix/UnixEndpoint.cpp b/src/add-ons/kernel/network/protocols/unix/UnixEndpoint.cpp
index b2d12b5d56..59524a4cd5 100644
--- a/src/add-ons/kernel/network/protocols/unix/UnixEndpoint.cpp
+++ b/src/add-ons/kernel/network/protocols/unix/UnixEndpoint.cpp
@@ -239,22 +239,25 @@ UnixEndpoint::Listen(int backlog)
 
 	if (!IsBound())
 		RETURN_ERROR(EDESTADDRREQ);
-	if (fState != UNIX_ENDPOINT_NOT_CONNECTED)
+	if (fState != UNIX_ENDPOINT_NOT_CONNECTED
+		&& fState != UNIX_ENDPOINT_LISTENING)
 		RETURN_ERROR(EINVAL);
 
 	gSocketModule->set_max_backlog(socket, backlog);
 
-	fAcceptSemaphore = create_sem(0, "unix accept");
-	if (fAcceptSemaphore < 0)
-		RETURN_ERROR(ENOBUFS);
-
-	_UnsetReceiveFifo();
-
-	fCredentials.pid = getpid();
-	fCredentials.uid = geteuid();
-	fCredentials.gid = getegid();
-
-	fState = UNIX_ENDPOINT_LISTENING;
+	if (fState == UNIX_ENDPOINT_NOT_CONNECTED) {
+		fAcceptSemaphore = create_sem(0, "unix accept");
+		if (fAcceptSemaphore < 0)
+			RETURN_ERROR(ENOBUFS);
+	
+		_UnsetReceiveFifo();
+	
+		fCredentials.pid = getpid();
+		fCredentials.uid = geteuid();
+		fCredentials.gid = getegid();
+	
+		fState = UNIX_ENDPOINT_LISTENING;
+	}
 
 	RETURN_ERROR(B_OK);
 }