diff --git a/src/ca/client/CAref.html b/src/ca/client/CAref.html
index 46a0fc9e5..6c951b1b2 100644
--- a/src/ca/client/CAref.html
+++ b/src/ca/client/CAref.html
@@ -324,6 +324,11 @@ is used.</p>
       <td>r &gt; 60 seconds</td>
       <td>300</td>
     </tr>
+    <tr>
+      <td>EPICS_CA_MCAST_TTL</td>
+      <td>r &gt; 1</td>
+      <td>1</td>
+    </tr>
     <tr>
       <td>EPICS_TS_MIN_WEST</td>
       <td>-720 &lt; i &lt;720 minutes</td>