diff --git a/cmd/proxy/actions/app_proxy.go b/cmd/proxy/actions/app_proxy.go
index 5e39fe1bb..7a7846ce0 100644
--- a/cmd/proxy/actions/app_proxy.go
+++ b/cmd/proxy/actions/app_proxy.go
@@ -43,6 +43,20 @@ func addProxyRoutes(
 	}
 	r.HandleFunc("/index", indexHandler(indexer))
 
+	var firstGoProxyUrl *url.URL
+	if goBinVarProxy, has := c.GoBinaryEnvVars.GetValue("GOPROXY"); has {
+		for _, proxy := range strings.Split(goBinVarProxy, ",") {
+			if proxy == "direct" {
+				continue
+			}
+			firstGoProxyUrl, err = url.Parse(proxy)
+			if err != nil {
+				return err
+			}
+			break
+		}
+	}
+
 	for _, sumdb := range c.SumDBs {
 		sumdbURL, err := url.Parse(sumdb)
 		if err != nil {
@@ -55,11 +69,21 @@ func addProxyRoutes(
 		r.HandleFunc(supportPath, func(w http.ResponseWriter, r *http.Request) {
 			w.WriteHeader(200)
 		})
-		sumHandler := sumdbProxy(sumdbURL, c.NoSumPatterns)
-		pathPrefix := "/sumdb/" + sumdbURL.Host
-		r.PathPrefix(pathPrefix + "/").Handler(
-			http.StripPrefix(strings.TrimSuffix(c.PathPrefix, "/")+pathPrefix, sumHandler),
-		)
+
+		var sumHandler http.Handler
+		if sumdbURL.Host == "sum.golang.org" && firstGoProxyUrl != nil{
+			pathPrefix := "/sumdb/" + sumdbURL.Host
+			sumdbURL.Scheme = firstGoProxyUrl.Scheme
+			sumdbURL.Host = firstGoProxyUrl.Host
+			sumHandler = sumdbProxy(sumdbURL, c.NoSumPatterns)
+			r.PathPrefix(pathPrefix + "/").Handler(sumHandler)
+		} else {
+			sumHandler = sumdbProxy(sumdbURL, c.NoSumPatterns)
+			pathPrefix := "/sumdb/" + sumdbURL.Host
+			r.PathPrefix(pathPrefix + "/").Handler(
+				http.StripPrefix(strings.TrimSuffix(c.PathPrefix, "/")+pathPrefix, sumHandler),
+			)
+		}
 	}
 
 	// Download Protocol
diff --git a/pkg/config/config.go b/pkg/config/config.go
index 1bd9fa08d..c9b645c9a 100644
--- a/pkg/config/config.go
+++ b/pkg/config/config.go
@@ -77,6 +77,16 @@ func (el EnvList) HasKey(key string) bool {
 	return false
 }
 
+func (el EnvList) GetValue(key string) (string, bool){
+	prefix := key+"="
+	for _, env := range el {
+		if strings.HasPrefix(env, prefix) {
+			return env[len(prefix):], true
+		}
+	}
+	return "", false
+}
+
 // Add adds a key=value entry to the environment
 // list
 func (el *EnvList) Add(key, value string) {