diff --git a/rainloop/v/0.0.0/app/libraries/MailSo/Smtp/SmtpClient.php b/rainloop/v/0.0.0/app/libraries/MailSo/Smtp/SmtpClient.php
index 4618aa178..f204444eb 100644
--- a/rainloop/v/0.0.0/app/libraries/MailSo/Smtp/SmtpClient.php
+++ b/rainloop/v/0.0.0/app/libraries/MailSo/Smtp/SmtpClient.php
@@ -111,6 +111,32 @@ class SmtpClient extends \MailSo\Net\NetClient
 		return $this->IsAuthSupported('PLAIN') || $this->IsAuthSupported('LOGIN');
 	}
 
+	/**
+	 * @return string
+	 */
+	public static function EhloHelper()
+	{
+		$sEhloHost = empty($_SERVER['SERVER_NAME']) ? '' : \trim($_SERVER['SERVER_NAME']);
+		if (empty($sEhloHost))
+		{
+			$sEhloHost = empty($_SERVER['HTTP_HOST']) ? '' : \trim($_SERVER['HTTP_HOST']);
+		}
+		
+		if (empty($sEhloHost))
+		{
+			$sEhloHost = \function_exists('gethostname') ? \gethostname() : 'localhost';
+		}
+
+		$sEhloHost = \trim(\preg_replace('/:\d+$/', '', \trim($sEhloHost)));
+
+		if (\preg_match('/^\d+\.\d+\.\d+\.\d+$/', $sEhloHost))
+		{
+			$sEhloHost = '['.$sEhloHost.']';
+		}
+
+		return empty($sEhloHost) ? 'localhost' : $sEhloHost;
+	}
+
 	/**
 	 * @param string $sServerName
 	 * @param int $iPort = 25
diff --git a/rainloop/v/0.0.0/app/libraries/RainLoop/Actions.php b/rainloop/v/0.0.0/app/libraries/RainLoop/Actions.php
index e2309b03c..777df3ae2 100644
--- a/rainloop/v/0.0.0/app/libraries/RainLoop/Actions.php
+++ b/rainloop/v/0.0.0/app/libraries/RainLoop/Actions.php
@@ -3732,7 +3732,7 @@ class Actions
 							$sFrom = $oFrom instanceof \MailSo\Mime\Email ? $oFrom->GetEmail() : '';
 
 							$aSmtpCredentials = array(
-								'Ehlo' => \function_exists('gethostname') ? \gethostname() : 'localhost',
+								'Ehlo' => \MailSo\Smtp\SmtpClient::EhloHelper(),
 								'Host' => $oAccount->Domain()->OutHost(),
 								'Port' => $oAccount->Domain()->OutPort(),
 								'Secure' => $oAccount->Domain()->OutSecure(),