[Dnsmasq-discuss] Dynamic address config?

[Petr Menšík]

Did you know that dnsmasq registers all hosts by their name, if they 
send their own hostname when requesting DHCP from dnsmasq? Just use 
domain=mylab and have that host send hostname. It would make using names 
possible without any additional configuration.

I do not get what is the advantage of having IP suffixed by some domain. 
It looks like IP address, but it is even longer. Names of machines 
should be easy to remember or use, I doubt that would be the case here.

I think we have new feature conf-script, which can generate dnsmasq 
configuration on the output. But I doubt we have a possible code for 
what you describe. Could you please describe more about intended usage? 
Why isn't using just hostname for each host enough? Using dhcp-host 
seems enough for similar uses.

I think DLZ plugins for BIND9 are able to do similar things to your 
request, but that would be very heavy-weight solution. I think more 
motivation for your current design should be shared, because I do not 
understand advantage of your solution.

Cheers,
Petr

On 11/23/22 06:47, Feng Shao wrote:
> There are a bunch of machines in our lab, and we normally don't have 
> DNS records configured for them, only accessing by IP. In order to ssh 
> to them with key auth, I have a config in my .ssh/config like
>
> Host *.mylab
>   User root
>   IdentityFile ~/.ssh/id_rsa.work <http://id_rsa.work/>
>
> and I have some "address=/123.123.123.123 
> <http://123.123.123.123>.mylab/123.123.123.123 
> <http://123.123.123.123/>" line in dnsmasq.conf. The problem here is I 
> need to add an entry whenever a new IP comes.
>
> Can this configuration be dynamically? For example, 
> "address=/*.mylab/somecmd %1", where "somecmd" is a external command 
> and %1 will be replaced by the name in A/AAAA request. So that for any 
> DNS request to *.mylab, dnsmasq invoke this external command and pass 
> the name as argument, the output of external command, which will be 
> interpreted as IPv4/IPv6 addr then responsed to client?
>
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-- 
Petr Menšík
Software Engineer, RHEL
Red Hat,https://www.redhat.com/
PGP: DFCF908DB7C87E8E529925BC4931CA5B6C9FC5CB
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