diff --git a/pkg/api/handlers/swagger/errors.go b/pkg/api/handlers/swagger/errors.go
index 18308d1b7b..1317cf783f 100644
--- a/pkg/api/handlers/swagger/errors.go
+++ b/pkg/api/handlers/swagger/errors.go
@@ -28,6 +28,13 @@ type networkNotFound struct {
 	Body errorhandling.ErrorModel
 }
 
+// Network is already connected and container is running or transitioning to the running state ('initialized')
+// swagger:response
+type networkConnectedError struct {
+	// in:body
+	Body errorhandling.ErrorModel
+}
+
 // No such exec instance
 // swagger:response
 type execSessionNotFound struct {
diff --git a/pkg/api/server/register_networks.go b/pkg/api/server/register_networks.go
index eb95e0d8cc..50f1ffb9b9 100644
--- a/pkg/api/server/register_networks.go
+++ b/pkg/api/server/register_networks.go
@@ -125,7 +125,7 @@ func (s *APIServer) registerNetworkHandlers(r *mux.Router) error {
 	// tags:
 	//  - networks (compat)
 	// summary: Connect container to network
-	// description: Connect a container to a network.  This endpoint is current a no-op
+	// description: Connect a container to a network
 	// produces:
 	// - application/json
 	// parameters:
@@ -144,6 +144,8 @@ func (s *APIServer) registerNetworkHandlers(r *mux.Router) error {
 	//     description: OK
 	//   400:
 	//     $ref: "#/responses/badParamError"
+	//   403:
+	//     $ref: "#/responses/networkConnectedError"
 	//   500:
 	//     $ref: "#/responses/internalError"
 	r.HandleFunc(VersionedPath("/networks/{name}/connect"), s.APIHandler(compat.Connect)).Methods(http.MethodPost)
@@ -153,7 +155,7 @@ func (s *APIServer) registerNetworkHandlers(r *mux.Router) error {
 	// tags:
 	//  - networks (compat)
 	// summary: Disconnect container from network
-	// description: Disconnect a container from a network.  This endpoint is current a no-op
+	// description: Disconnect a container from a network
 	// produces:
 	// - application/json
 	// parameters: