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<DIV><FONT face="Courier New" size=2>Arnoud wrote:</FONT></DIV>
<DIV><FONT face="Courier New" size=2>> We use bind for DNS.<BR>> At the
moment we have one primary server that delegates updates to it`s two slave
servers.<BR>> <BR>> Since everything nowadays is dependant on DNS I would
like to cluster my primary server in case of a hardware failure or
error.<BR>> <BR>> So, how do I setup two primary bind servers that keep
each other in sync one way or the other.<BR>> I`ve been surfing the internet,
but couldn`t find any satisfactory solution.<BR></FONT></DIV>
<DIV><FONT size=2><FONT face="Courier New" size=2>I've never tried this, but I
think it might work:</FONT></FONT></DIV>
<DIV><FONT size=2><FONT face="Courier New" size=2></FONT></FONT> </DIV>
<DIV><FONT face="Courier New" size=2>The hard part of this is the dynamic DNS,
so looking at that part of it</FONT></DIV>
<DIV><FONT face="Courier New" size=2>first....</FONT></DIV>
<DIV><FONT size=2><FONT face="Courier New" size=2></FONT></FONT> </DIV>
<DIV><FONT size=2><FONT face="Courier New" size=2>Use multiple slave servers in
an anycast architecture for the published</FONT></FONT></DIV>
<DIV><FONT size=2><FONT face="Courier New" size=2>MNAME server, and use
</FONT></FONT><FONT size=2><FONT face="Courier New" size=2>update forwarding on
the slave servers to replicate</FONT></FONT></DIV>
<DIV><FONT size=2><FONT face="Courier New" size=2>DDNS to multiple hidden
masters. The </FONT></FONT><FONT size=2><FONT face="Courier New"
size=2>slaves would then all zone-transfer</FONT></FONT></DIV>
<DIV><FONT size=2><FONT face="Courier New" size=2>the info back from the hidden
masters.</FONT></FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2>To conserve hardware, you can have 2
instances of BIND on a single server</FONT></DIV>
<DIV><FONT face="Courier New" size=2>so that each slave </FONT><FONT
face="Courier New" size=2>has a hidden master on the same box.</FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2>The key to anycasting is that if a slave
server stops working, the host</FONT></DIV>
<DIV><FONT face="Courier New" size=2>route to that server </FONT><FONT
face="Courier New" size=2>must be removed from the router asap. This can
be</FONT></DIV>
<DIV><FONT face="Courier New" size=2>done best using Cisco routers with static
</FONT><FONT face="Courier New" size=2>routes that track "ip sla"</FONT></DIV>
<DIV><FONT face="Courier New" size=2>monitors configured to check DNS.
Otherwise it can be done using </FONT><FONT face="Courier New"
size=2>OSPF</FONT></DIV>
<DIV><FONT face="Courier New" size=2>between the server and the router with
self-monitoring scripts on the</FONT></DIV>
<DIV><FONT face="Courier New" size=2>servers that take </FONT><FONT
face="Courier New" size=2>down the loopback interface if the service is
down.</FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2>For the non-dynamic DNS, you can
h</FONT><FONT size=2><FONT face="Courier New" size=2>ave all masters share a
common NAS</FONT></FONT></DIV>
<DIV><FONT size=2><FONT face="Courier New" size=2>directory for non-dynamic
</FONT></FONT><FONT size=2><FONT face="Courier New" size=2>zone files as well as
the shared conf file</FONT></FONT></DIV>
<DIV><FONT size=2><FONT face="Courier New" size=2>-- but keep the dynamic
(and slave) data in local </FONT></FONT><FONT size=2><FONT
face="Courier New" size=2>directories. Any time</FONT></FONT></DIV>
<DIV><FONT size=2><FONT face="Courier New" size=2>the non-dynamic data changes,
you will need to "kill -1" all of the BIND</FONT></FONT></DIV>
<DIV><FONT size=2><FONT face="Courier New" size=2>processes configured as master
for the affected zones. This can be</FONT></FONT></DIV>
<DIV><FONT size=2><FONT face="Courier New" size=2>automated with scripts using
</FONT></FONT><FONT size=2><FONT face="Courier New"
size=2>rndc.</FONT></FONT></DIV>
<DIV><FONT size=2><FONT face="Courier New"></FONT></FONT> </DIV>
<DIV><FONT size=2><FONT face="Courier New">I'd be glad to help further, but more
importantly I'd like to know how</FONT></FONT></DIV>
<DIV><FONT size=2><FONT face="Courier New">well it works for you before I dare
try it myself.</FONT></FONT></DIV>
<DIV><FONT size=2><FONT face="Courier New"></FONT></FONT> </DIV>
<DIV><FONT size=2><FONT face="Courier New">;-)</FONT></DIV>
<DIV><FONT face=Arial></FONT><FONT face=Arial></FONT><BR><FONT
face="Courier New">--<BR>Gordon A. Lang /
313-819-7978</FONT></FONT></DIV></BODY></HTML>