From a7ac3339def8d07d825d64f33e8ca69c21dd2743 Mon Sep 17 00:00:00 2001
From: Michael Foster <savetheinternet@tinyboard.org>
Date: Wed, 28 Aug 2013 17:00:41 +1000
Subject: [PATCH] DNS(): Cache NXDOMAIN

---
 inc/functions.php | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/inc/functions.php b/inc/functions.php
index afebd5d8..6ce0b29e 100644
--- a/inc/functions.php
+++ b/inc/functions.php
@@ -1940,7 +1940,7 @@ function DNS($host) {
 	global $config;
 
 	if ($config['cache']['enabled'] && ($ip_addr = cache::get('dns_' . $host))) {
-		return $ip_addr;
+		return $ip_addr != '?' ? $ip_addr : false;
 	}
 
 	if (!$config['dns_system']) {
@@ -1956,7 +1956,7 @@ function DNS($host) {
 	}
 
 	if ($config['cache']['enabled'])
-		cache::set('dns_' . $host, $ip_addr, 3600);
+		cache::set('dns_' . $host, $ip_addr !== false ? $ip_addr : '?', 3600);
 
 	return $ip_addr;
 }