--- whois.module.orig	2010-01-29 10:07:48.000000000 +0000
+++ whois.module	2010-01-29 10:37:00.000000000 +0000
@@ -203,17 +203,31 @@
   }
   elseif ($address != '') {
     $address = _whois_cleanup_address($address);
-    include_once($mod_path . '/phpwhois/whois.main.php');
-    include_once($mod_path . '/phpwhois/whois.utils.php');
-    $whois = new Whois();
-    if (variable_get('whois_log_watchdog', 1)) {
-      // Watchdog entry for lookup request.
-      watchdog('whois',
-        'Whois lookup for: %address',
-        array('%address' => $address),
-        WATCHDOG_NOTICE, l('View', "whois/$address") . ' · ' . l('Address', "http://$address/"));
+
+    // check cache first
+    $cid = 'whois-' . $address;
+    if (variable_get('whois_cache_enable', 1) && cache_get($cid, "cache") && !empty($cache->data)) {
+      $whois_results = $cache->data;
+    }
+    else {
+      include_once($mod_path . '/phpwhois/whois.main.php');
+      include_once($mod_path . '/phpwhois/whois.utils.php');
+      $whois = new Whois();
+      if (variable_get('whois_log_watchdog', 1)) {
+        // Watchdog entry for lookup request.
+        watchdog('whois',
+          'Whois lookup for: %address',
+          array('%address' => $address),
+          WATCHDOG_NOTICE, l('View', "whois/$address") . ' · ' . l('Address', "http://$address/"));
+      }
+      $whois_results = $whois->Lookup($address);
+
+      if (variable_get('whois_cache_enable', 1)) {
+        // cache results
+        cache_set($cid, $whois_results, "cache", variable_get("whois_cache_time", 86400));
+      }
     }
-    return $whois->Lookup($address);
+    return $whois_results;
   }
   return FALSE;
 }