fix withLocalhost: RemoteAddr is a host:port

fe/http.go

@@ -371,7 +371,12 @@ func (h *HttpRedirector) serveStatusPage(w http.ResponseWriter, r *http.Request)
 
 func withLocalhost(h http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		if ip := net.ParseIP(r.RemoteAddr); !ip.IsLoopback() {
+		host, _, err := net.SplitHostPort(r.RemoteAddr)
+		if err != nil {
+			http.Error(w, "Unauthorized", http.StatusUnauthorized)
+			return
+		}
+		if ip := net.ParseIP(host); !ip.IsLoopback() {
 			http.Error(w, "Unauthorized", http.StatusUnauthorized)
 			return
 		}