diff --git a/libbeat/esleg/eslegclient/connection.go b/libbeat/esleg/eslegclient/connection.go
index 3c6afea5aa8e..80032b8c1875 100644
--- a/libbeat/esleg/eslegclient/connection.go
+++ b/libbeat/esleg/eslegclient/connection.go
@@ -18,11 +18,13 @@
 package eslegclient
 
 import (
+	"bufio"
 	"bytes"
 	"encoding/base64"
 	"encoding/json"
 	"fmt"
 	"io"
+	"net"
 	"net/http"
 	"net/url"
 	"time"
@@ -312,13 +314,70 @@ func (conn *Connection) Close() error {
 	return nil
 }
 
+type httpClientProxySettings struct {
+	*httpcommon.HTTPClientProxySettings
+}
+
+// ProxyDialer is a dialer that can be registered to golang.org/x/net/proxy
+func (settings *httpClientProxySettings) ProxyDialer(_ *url.URL, forward proxy.Dialer) (proxy.Dialer, error) {
+	return transport.DialerFunc(func(_, address string) (net.Conn, error) {
+
+		// Headers given to the CONNECT request
+		hdr := settings.Headers.Headers()
+		if settings.URL.User != nil {
+			username := settings.URL.User.Username()
+			password, _ := settings.URL.User.Password()
+			if len(hdr) == 0 {
+				hdr = http.Header{}
+			}
+			hdr.Add("Proxy-Authorization", "Basic "+base64.StdEncoding.EncodeToString([]byte(username+":"+password)))
+		}
+
+		req := &http.Request{
+			Method: "CONNECT",
+			URL:    &url.URL{Opaque: address},
+			Host:   address,
+			Header: hdr,
+		}
+
+		// Dial the proxy host
+		c, err := forward.Dial("tcp", settings.URL.Host)
+		if err != nil {
+			return nil, err
+		}
+
+		// Write the CONNECT request
+		err = req.Write(c)
+		if err != nil {
+			c.Close()
+			return nil, err
+		}
+
+		res, err := http.ReadResponse(bufio.NewReader(c), req)
+		if err != nil {
+			c.Close()
+			return nil, err
+		}
+		res.Body.Close()
+
+		if res.StatusCode != http.StatusOK {
+			c.Close()
+			return nil, fmt.Errorf("proxy server returned status code %d", res.StatusCode)
+		}
+
+		return c, nil
+	}), nil
+}
+
 func (conn *Connection) Test(d testing.Driver) {
 	testProxyDialer := func(d testing.Driver, forward transport.Dialer, settings *httpcommon.HTTPClientProxySettings) transport.Dialer {
 		switch scheme := settings.URL.Scheme; scheme {
 		case "http", "https":
-			proxy.RegisterDialerType(scheme, settings.ProxyDialer)
+			proxy.RegisterDialerType(scheme, (&httpClientProxySettings{HTTPClientProxySettings: settings}).ProxyDialer)
 		}
-		return transport.TestProxyDialer(d, forward, &transport.ProxyConfig{URL: settings.URL.String()})
+		dialer, err := transport.ProxyDialer(logp.L(), &transport.ProxyConfig{URL: settings.URL.String()}, forward)
+		d.Fatal("proxy", err)
+		return dialer
 	}
 
 	d.Run("elasticsearch: "+conn.URL, func(d testing.Driver) {