DDNS and Failover

[Glenn Satchell]

On Wed, May 8, 2013 3:19 pm, Chris Buxton wrote:
> On May 2, 2013, at 11:19 PM, Peter Fraser <petros.fraser at gmail.com> wrote:
>
>> I would like to understand how a scenario would play out if I have DDNS
>> as well as DHCP Failover working. Let's say I have DHCP1/DNS1 and
>> DHCP2/DNS2
>>
>> DHCP1/DNS1 goes down. Users would then get IP addresses from DHCP2/DNS2
>> How would the DNS records of DHCP2/DNS2 be updated?
>>
>> Could things be configured so that it DHCP1/DNS1 goes down, DHCP2/DNS2
>> would update its own DNS records and when DHCP1/DNS1 comes back online,
>> it somehow gets the updates. I wondering if that's even possible. Is it?
>
>
> Not possible using BIND. You would need a multi-master DNS server.
>
> Chris

However, if dhcpd is not able to do the dns update then no ddns entry is
added to the lease. Each time the lease is renewed it will try to do the
dns update. For long lived systems then it will eventually get added to
dns.

Not a perfect solution though. TO get around this, as Chris suggests use a
multi-master DNs server, or use an HA cluster to do do your primary dns
server.

regards,
-glenn