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

Chris Green cl at isbd.net
Fri Sep 3 20:23:01 UTC 2021


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'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.

So the normal 'everything working' situation will be system A (say on
192.168.1.2) is a DNS and DHCP server.  System B (say on 192.168.1.3)
provides only DNS.  System A's DHCP server will give out both
192.168.1.2 and 192.168.1.3 as DNS servers.

If 192.168.1.3 fails or is off line everything continues to work OK
except maybe some slowing down of DNS because of requests to
192.168.1.3 having to timeout before retrying on 192.168.1.2.

If 192.168.1.2 fails I will add the DHCP configuration to it
'manually' and then I'll have a working system while I fix
192.168.1.2.

-- 
Chris Green



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