diff --git a/src/net/http/httputil/dump.go b/src/net/http/httputil/dump.go
index ac8f103f9b..ca2d1cde92 100644
--- a/src/net/http/httputil/dump.go
+++ b/src/net/http/httputil/dump.go
@@ -98,6 +98,14 @@ func DumpRequestOut(req *http.Request, body bool) ([]byte, error) {
 	defer pr.Close()
 	defer pw.Close()
 	dr := &delegateReader{c: make(chan io.Reader)}
+
+	t := &http.Transport{
+		Dial: func(net, addr string) (net.Conn, error) {
+			return &dumpConn{io.MultiWriter(&buf, pw), dr}, nil
+		},
+	}
+	defer t.CloseIdleConnections()
+
 	// Wait for the request before replying with a dummy response:
 	go func() {
 		req, err := http.ReadRequest(bufio.NewReader(pr))
@@ -107,16 +115,9 @@ func DumpRequestOut(req *http.Request, body bool) ([]byte, error) {
 			io.Copy(ioutil.Discard, req.Body)
 			req.Body.Close()
 		}
-		dr.c <- strings.NewReader("HTTP/1.1 204 No Content\r\n\r\n")
+		dr.c <- strings.NewReader("HTTP/1.1 204 No Content\r\nConnection: close\r\n\r\n")
 	}()
 
-	t := &http.Transport{
-		DisableKeepAlives: true,
-		Dial: func(net, addr string) (net.Conn, error) {
-			return &dumpConn{io.MultiWriter(&buf, pw), dr}, nil
-		},
-	}
-
 	_, err := t.RoundTrip(reqSend)
 
 	req.Body = save