[Dnsmasq-discuss] Is there any way to give clients a secondary DNS for when the dnsmasq server isn't running?

[/dev/rob0]

On Thu, Dec 27, 2012 at 11:42:54PM +0000, Chris Green wrote:
> I run dnsmasq on my home server to provide DHCP and DNS services 
> for the home LAN.  The server is up just about all the time but 
> there are odd occasions when it's not available for more than just 
> the time required for a reboot (e.g. OS upgrades and disk checks 
> afer a reboot).

Hmm, I only reboot when the power outage exceeds the UPS capacity, or 
for kernel upgrades. :)

> Can dnsmasq supply a secondary DNS server to DHCP clients (when 
> they boot) so that, if the dnsmasq server machine is down for a 
> while, clients can carry on working?

Sure, see -O, --dhcp-option in the man page. The particular option 
you're seeking is #6, "dns-server". Looks like you would give it 
as such:

dhcp-option=6,0.0.0.0,other.ip.add.ress

However this fix might make more problems when clients switch to the 
secondary during an outage, if that secondary is unaware of the 
internal names. Perhaps a better idea is to schedule your outages 
better, or to run another dnsmasq.
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