diff --git a/ipv6-update.rsc b/ipv6-update.rsc
index c6e3d65..beccde0 100644
--- a/ipv6-update.rsc
+++ b/ipv6-update.rsc
@@ -20,7 +20,9 @@
   :global ScriptLock;
 
   :local NaAddress $"na-address";
+  :local NaValid $"na-valid";
   :local PdPrefix $"pd-prefix";
+  :local PdValid $"pd-valid";
 
   :if ([ $ScriptLock $ScriptName ] = false) do={
     :set ExitOK true;
@@ -39,6 +41,12 @@
     :error false;
   }
 
+  :if ($PdValid != 1) do={
+    $LogPrint info $ScriptName ("The prefix " . $PdPrefix . " is no longer valid. Ignoring.");
+    :set ExitOK true;
+    :error false;
+  }
+
   :local Pool [ /ipv6/pool/get [ find where prefix=$PdPrefix ] name ];
   :if ([ :len [ /ipv6/firewall/address-list/find where comment=("ipv6-pool-" . $Pool) ] ] = 0) do={
     /ipv6/firewall/address-list/add list=("ipv6-pool-" . $Pool) address=:: comment=("ipv6-pool-" . $Pool) dynamic=yes;