[Dnsmasq-discuss] Details of the --dhcp-optsdir=<path> option

Chris Green cl at isbd.net
Sat Sep 4 08:15:18 UTC 2021

On Fri, Sep 03, 2021 at 02:32:06PM -0700, Michael wrote:
> On 9/3/21 1:23 PM, Chris Green wrote:
> > If I have set dhcp-optsdir in /etc/dnsmasq.conf and add a file to the
> > directory it points to I assume any extra configuration in the added
> > file will 'just happen' without any restart or signalling of dnsmasq.
> > 
> > However (like the description for dhcp-hostsdir I presume that an
> > option I have added as above will not be removed if I delete the added
> > file.  Specifically if I put a dhcp-range option in the added file
> > (when there wasn't one in /etc/dnsmasq.conf) the DHCP server in
> > dnsmasq will be turned on, but removing the file won't turn the DHCP
> > server off again.  I'd need to restart dnsmasq to turn the DHCP server
> > off (or would one of the signals suffice?).
> I believe this is correct.
> > 
> > I'm thinking of running dnsmasq on two systems on my LAN to provide
> > some resilience.  One will be configured to run DHCP as well as DNS,
> > the other will be DNS only.  Apart from DHCP the configurations
> > will be identical and the IPs of both systems will be given by the
> > DHCP server as DNS IPs.
> This works if your DHCP server only hands out static addressing so the host
> names are all listed in the /etc/hosts or addn hosts location on both
> machines.   If the DHCP server is handing out addresses from a pool, then
> only the DHCP dnsmasq instance will know about those hosts by name.
I was aiming to synchronise the lease file in /var between the two
systems as well as the configuration.

Chris Green

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