diff --git a/phpBB/includes/functions_messenger.php b/phpBB/includes/functions_messenger.php
index 0d1c215cb1..909609d893 100644
--- a/phpBB/includes/functions_messenger.php
+++ b/phpBB/includes/functions_messenger.php
@@ -1134,7 +1134,7 @@ class smtp_class
 		global $user;
 
 		$err_msg = '';
-		$local_host = (function_exists('php_uname')) ? gethostbyaddr(gethostbyname(php_uname('n'))) : $user->host;
+		$local_host = (function_exists('php_uname') && function_exists('gethostbyaddr') && function_exists('gethostbyname')) ? gethostbyaddr(gethostbyname(php_uname('n'))) : $user->host;
 
 		// If we are authenticating through pop-before-smtp, we
 		// have to login ones before we get authenticated
diff --git a/phpBB/includes/session.php b/phpBB/includes/session.php
index dcfde14159..d8362d5089 100644
--- a/phpBB/includes/session.php
+++ b/phpBB/includes/session.php
@@ -182,7 +182,7 @@ class session
 			else
 			{
 				// Set to OS hostname or localhost
-				$host = (function_exists('php_uname')) ? gethostbyaddr(gethostbyname(php_uname('n'))) : 'localhost';
+				$host = (function_exists('php_uname') && function_exists('gethostbyaddr') && function_exists('gethostbyname')) ? gethostbyaddr(gethostbyname(php_uname('n'))) : 'localhost';
 			}
 		}