Move SMTP HELO before authentication (#6464)

utils/mail.go

@@ -50,6 +50,15 @@ func newSMTPClient(conn net.Conn, config *model.Config) (*smtp.Client, *model.Ap
 		return nil, model.NewLocAppError("SendMail", "utils.mail.connect_smtp.open_tls.app_error", nil, err.Error())
 	}
 
+	hostname := GetHostnameFromSiteURL(*config.ServiceSettings.SiteURL)
+	if hostname != "" {
+		err := c.Hello(hostname)
+		if err != nil {
+			l4g.Error(T("utils.mail.new_client.helo.error"), err)
+			return nil, model.NewLocAppError("SendMail", "utils.mail.connect_smtp.helo.app_error", nil, err.Error())
+		}
+	}
+
 	auth := smtp.PlainAuth("", config.EmailSettings.SMTPUsername, config.EmailSettings.SMTPPassword, config.EmailSettings.SMTPServer+":"+config.EmailSettings.SMTPPort)
 	if config.EmailSettings.ConnectionSecurity == model.CONN_SECURITY_TLS {
 		if err = c.Auth(auth); err != nil {
@@ -136,15 +145,6 @@ func SendMailUsingConfig(to, subject, body string, config *model.Config) *model.
 	defer c.Quit()
 	defer c.Close()
 
-	siteName := GetSiteName(*config.ServiceSettings.SiteURL)
-	if siteName != "" {
-		err := c.Hello(siteName)
-		if err != nil {
-			l4g.Error(T("utils.mail.new_client.helo.error"), err)
-			return model.NewLocAppError("SendMail", "utils.mail.connect_smtp.helo.app_error", nil, err.Error())
-		}
-	}
-
 	if err := c.Mail(fromMail.Address); err != nil {
 		return model.NewLocAppError("SendMail", "utils.mail.send_mail.from_address.app_error", nil, err.Error())
 	}

utils/utils.go

@@ -68,7 +68,7 @@ func GetIpAddress(r *http.Request) string {
 	return address
 }
 
-func GetSiteName(siteURL string) string {
+func GetHostnameFromSiteURL(siteURL string) string {
 	u, err := url.Parse(siteURL)
 	if err != nil {
 		return ""