[Dnsmasq-discuss] DNS from dhcp-host while client is offline

john doe johndoe65534 at mail.com
Tue Oct 5 14:34:17 UTC 2021

On 10/5/2021 2:43 PM, Michael wrote:
> On 10/4/21 05:37, Dominik Derigs wrote:
>> Hey Petr,
>> On Mon, 2021-10-04 at 11:45 +0200, Petr Menšík wrote:
>>> Perhaps a flag could be added to dhcp-range, requesting also
>>> addition of dhcp-hosts to static dns.
>> Maybe this flag would better be set on --dhcp-host and --dhcp-
>> hostsfile if this is used? This would feel more "natural" to me.
>> Initially, I've myself found this an odd behavior to only serve
>> only DHCP host names that are known to be "alive". I do see some
>> value in not serving A records when we know the server is
>> offline, however, the very same happens on the Internet all the
>> time: no DNS server I'm aware of checks if an A record is
>> reachable before giving you the reply.
>> I've seen other systems using dnsmasq (it may or not have been
>> DD-WRT, no promises!) that created two files from static leases:
>> A dhcp-hostsfile and an addn-hosts file. Having an option to make
>> the latter obsolete sounds like a good idea.
> Maybe I am misunderstanding the issue, but dnsmasq already give the
> ability that is being asked for I believe.
> If you want a static DNS entry, add the entry to /etc/hosts or -addn-hosts=
> If you want a DHCP lease that always hands out the same ip address but
> is only valid during the lease, create a dhcp-host entry that includes
> the IP & hostname
> If you want a DHCP lease can always be looked up via DNS, add it to
> /etc/hosts or -addn-hosts and the dhcp-host entry contains the hostname

The idea here is to let Dnsmasq do that programatically instead of
having to do it manually.

John Doe

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