From 26618f525b111a4c081fb5068ad7020704415fd8 Mon Sep 17 00:00:00 2001
From: sxntxn <44604448+sxntxn@users.noreply.github.com>
Date: Wed, 8 Jul 2020 05:39:23 +0200
Subject: [PATCH] Add option to configure SMTP HELO hostname

---
 app/Core/Mail/Transport/Smtp.php | 3 +++
 app/constants.php                | 1 +
 config.default.php               | 1 +
 3 files changed, 5 insertions(+)

diff --git a/app/Core/Mail/Transport/Smtp.php b/app/Core/Mail/Transport/Smtp.php
index 7338a81ef..d17c52a0e 100644
--- a/app/Core/Mail/Transport/Smtp.php
+++ b/app/Core/Mail/Transport/Smtp.php
@@ -23,6 +23,9 @@ class Smtp extends Mail
         $transport = Swift_SmtpTransport::newInstance(MAIL_SMTP_HOSTNAME, MAIL_SMTP_PORT);
         $transport->setUsername(MAIL_SMTP_USERNAME);
         $transport->setPassword(MAIL_SMTP_PASSWORD);
+        if (!is_null(MAIL_SMTP_HELO_NAME)) {
+                $transport->setLocalDomain(MAIL_SMTP_HELO_NAME);
+        }
         $transport->setEncryption(MAIL_SMTP_ENCRYPTION);
 
         if (HTTP_VERIFY_SSL_CERTIFICATE === false) {
diff --git a/app/constants.php b/app/constants.php
index 62f517fb9..8ffb4c40a 100644
--- a/app/constants.php
+++ b/app/constants.php
@@ -109,6 +109,7 @@ defined('MAIL_SMTP_HOSTNAME') or define('MAIL_SMTP_HOSTNAME', getenv('MAIL_SMTP_
 defined('MAIL_SMTP_PORT') or define('MAIL_SMTP_PORT', intval(getenv('MAIL_SMTP_PORT')) ?: 25);
 defined('MAIL_SMTP_USERNAME') or define('MAIL_SMTP_USERNAME', getenv('MAIL_SMTP_USERNAME') ?: '');
 defined('MAIL_SMTP_PASSWORD') or define('MAIL_SMTP_PASSWORD', getenv('MAIL_SMTP_PASSWORD') ?: '');
+defined('MAIL_SMTP_HELO_NAME') or define('MAIL_SMTP_HELO_NAME', getenv('MAIL_SMTP_HELO_NAME') ?: null);
 defined('MAIL_SMTP_ENCRYPTION') or define('MAIL_SMTP_ENCRYPTION', getenv('MAIL_SMTP_ENCRYPTION') ?: null);
 defined('MAIL_SENDMAIL_COMMAND') or define('MAIL_SENDMAIL_COMMAND', getenv('MAIL_SENDMAIL_COMMAND') ?: '/usr/sbin/sendmail -bs');
 
diff --git a/config.default.php b/config.default.php
index 66b2daa1f..2f70a6126 100644
--- a/config.default.php
+++ b/config.default.php
@@ -52,6 +52,7 @@ define('MAIL_SMTP_HOSTNAME', '');
 define('MAIL_SMTP_PORT', 25);
 define('MAIL_SMTP_USERNAME', '');
 define('MAIL_SMTP_PASSWORD', '');
+define('MAIL_SMTP_HELO_NAME', null); // valid: null (default), or FQDN
 define('MAIL_SMTP_ENCRYPTION', null); // Valid values are null (not a string "null"), "ssl" or "tls"
 
 // Sendmail command to use when the transport is "sendmail"