From 6e8c1bf1282105e6239c1b031bcaa324e712e1dc Mon Sep 17 00:00:00 2001
From: DL6ER <derigs@ph1.uni-koeln.de>
Date: Tue, 13 Dec 2016 17:22:58 +0100
Subject: [PATCH] Allow leaving Custom secondary DNS server field empty

---
 php/savesettings.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/php/savesettings.php b/php/savesettings.php
index 5a67f449..22bbc943 100644
--- a/php/savesettings.php
+++ b/php/savesettings.php
@@ -74,7 +74,7 @@ function validDomain($domain_name)
 				}
 
 				// Validate secondary IP
-				if (!validIP($secondaryIP))
+				if (!validIP($secondaryIP) && strlen($secondaryIP) > 0)
 				{
 					$error .= "Secondary IP (".$secondaryIP.") is invalid!<br>";
 				}