diff --git a/interop/client/main.go b/interop/client/main.go
index d6c0daaca..c8c81d0dc 100644
--- a/interop/client/main.go
+++ b/interop/client/main.go
@@ -62,6 +62,8 @@ func runTestcase(testcase string) error {
 		defer r.Close()
 		return downloadFiles(r, urls)
 	case "handshake", "transfer", "retry":
+	case "multiconnect":
+		return runMultiConnectTest(urls)
 	case "versionnegotiation":
 		return runVersionNegotiationTest(urls)
 	case "resumption":
@@ -90,6 +92,19 @@ func runVersionNegotiationTest(urls []string) error {
 	return nil
 }
 
+func runMultiConnectTest(urls []string) error {
+	for _, url := range urls {
+		r := &http09.RoundTripper{TLSClientConfig: tlsConf}
+		if err := downloadFile(r, url); err != nil {
+			return err
+		}
+		if err := r.Close(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 func runResumptionTest(urls []string) error {
 	if len(urls) < 2 {
 		return errors.New("expected at least 2 URLs")
diff --git a/interop/server/main.go b/interop/server/main.go
index 9b099f19c..791cb5754 100644
--- a/interop/server/main.go
+++ b/interop/server/main.go
@@ -42,7 +42,7 @@ func main() {
 	tlsConf.KeyLogWriter = keyLog
 
 	switch testcase {
-	case "versionnegotiation", "handshake", "transfer", "resumption":
+	case "versionnegotiation", "handshake", "transfer", "resumption", "multiconnect":
 		err = runHTTP09Server(quicConf)
 	case "retry":
 		// By default, quic-go performs a Retry on every incoming connection.