regen

FAQ.xml

@@ -17,7 +17,7 @@
  - PERFORMANCE OF THIS SOFTWARE.
 -->
 
-<!-- $Id: FAQ.xml,v 1.4.6.22 2008/06/01 01:21:11 tbox Exp $ -->
+<!-- $Id: FAQ.xml,v 1.4.6.23 2008/07/17 01:21:35 tbox Exp $ -->
 
 <article class="faq">
   <title>Frequently Asked Questions about BIND 9</title>
@@ -664,6 +664,76 @@ zone "list.dsbl.org" {
     
     </qandadiv> <!-- Configuration and Setup Questions -->
     
+    <qandadiv><title>Operations Questions</title>
+
+    <qandaentry>
+      <question>
+	<para>
+	  How to change the nameservers for a zone?
+	</para>
+      </question>
+      <answer>
+	<para>
+	  Step 1: Ensure all nameservers, new and old, are serving the
+	  same zone content.
+	</para>
+	<para>
+	  Step 2: Work out the maximum TTL of the NS RRset in the parent and child
+	  zones.  This is the time it will take caches to be clear of a
+	  particular version of the NS RRset.
+	  If you are just removing nameservers you can skip to Step 6.
+	</para>
+	<para>
+	  Step 3: Add new nameservers to the NS RRset for the zone and
+	  wait until all the servers for the zone are answering with this
+	  new NS RRset.
+	</para>
+	<para>
+	  Step 4: Inform the parent zone of the new NS RRset then wait for all the
+	  parent servers to be answering with the new NS RRset.
+	</para>
+	<para>
+	  Step 5: Wait for cache to be clear of the old NS RRset.
+	  See Step 2 for how long.
+	  If you are just adding nameservers you are done.
+	</para>
+	<para>
+	  Step 6: Remove any old nameservers from the zones NS RRset and
+	  wait for all the servers for the zone to be serving the new NS RRset.
+	</para>
+	<para>
+	  Step 7: Inform the parent zone of the new NS RRset then wait for all the
+	  parent servers to be answering with the new NS RRset.
+	</para>
+	<para>
+	  Step 8: Wait for cache to be clear of the old NS RRset.
+	  See Step 2 for how long.
+	</para>
+	<para>
+	  Step 9: Turn off the old nameservers or remove the zone entry from
+	  the configuration of the old nameservers.
+	</para>
+	<para>
+	  Step 10: Increment the serial number and wait for the change to
+	  be visible in all nameservers for the zone.  This ensures that
+	  zone transfers are still working after the old servers are
+	  decommissioned.
+	</para>
+	<para>
+	  Note: the above procedure is designed to be transparent
+	  to dns clients.  Decommissioning the old servers too early
+	  will result in some clients not being able to look up
+	  answers in the zone.
+	</para>
+	<para>
+	  Note: while it is possible to run the addition and removal
+	  stages together it is not recommended.
+	</para>
+      </answer>
+    </qandaentry>
+
+    </qandadiv> <!-- Operations Questions -->
+
     <qandadiv><title>General Questions</title>
 	    
     <qandaentry>