diff --git a/source/php/ExternalDetector.php b/source/php/ExternalDetector.php
index 99cdfb2..6c53ba7 100644
--- a/source/php/ExternalDetector.php
+++ b/source/php/ExternalDetector.php
@@ -252,6 +252,13 @@ public function isValidDomainName($domainName)
      */
     public function isDomainAvailable($url, $timeOut = 7)
     {
+        if (!function_exists('curl_init')) {
+            if(defined("BROKEN_LINKS_LOG") && BROKEN_LINKS_LOG) {
+                error_log("Broken links: Could not probe url " . $url . " due lack of curl in this environment."); 
+            }
+            return true;
+        }
+
         // Init curl
         $ch = curl_init($url);
         curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.13) Gecko/20080311 Firefox/2.0.0.13');