[Dnsmasq-discuss] Automatic DHCP client naming

[richardvoigt at gmail.com]

Also, the dhcp-host line automatically adds the host to the "known"
group.  You may find it helpful to put a very short lease time (say 3
minutes) on "#known" and a normal lease time on "known".

On Fri, Apr 16, 2010 at 3:04 PM, Simon Kelley <simon at thekelleys.org.uk> wrote:
> Ferenc Wagner wrote:
>> Simon Kelley <simon at thekelleys.org.uk> writes:
>>
>>> Ferenc Wagner wrote:
>>>
>>>> Is there any way in dnsmasq to push a hostname to a DHCP client even if
>>>> it didn't report (or ask for) one?
>>> This much is easy:
>>> dhcp-host=00:11:22:33:44:55,myhost
>>
>> Yeah, it isn't a problem in itself.
>>
>>>> I'd like to automatically name my clients based on their MAC
>>>> addresses, like 00:11:22:33:44:55 should get the hostname
>>>> 00-11-22-33-44-55.domain.tld.
>>> That's not possible, other then by enumerating all possible MAC
>>> addresses in the configuration file.
>>
>> That sure would make for a biggish configuration file...
>>
>>>> Currently, I can get this effect only if the client sends its
>>>> hostname in the DHCP request; then dnsmasq adds the correct domain,
>>>> registers the name in its DNS database and sends back the fully
>>>> qualified address.  Good.  But I'd like to avoid generating the
>>>> hostname on the clients before starting DHCP.
>>> It would be possible to add that functionality, probably with something
>>> like dhcp-ignore-names, say "dhcp-mac-as-name", but only for a fixed
>>> name format (should there be a prefix?)
>>
>> Hmm, I'd rather extend the wildcarding already present in dhcp-mac with
>> something like
>>
>> dhcp-mac=*:*:*:*:*:*,PREFIX*-*-*-*-*-*SUFFIX
>>
>> or
>>
>> dhcp-mac=*,PREFIX*SUFFIX
>>
>> with the replacement of colons implied.  On the other hand, I've found
>> http://thread.gmane.org/gmane.network.dns.dnsmasq.general/3774/focus=3778
>> just now...  Well, managing a registry from dhcp-script is almost
>> acceptable, apart from the first run.  Here is another idea: why not let
>> dhcp-script write back the hostname to dnsmasq?  That way no separate
>> registry nor daemon restarts would be needed.
>
> Restart aren't needed: it's possible to re-read dhcp-host  lines on
> SIGHUP is they are kept in a separate file.
>
> Getting data back from the dhcp-script is very difficult: it executes
> somewhat asynchronously so that the daemon can't ever be blocked waiting
> for a script to finish.
>
>
> Simon.
>
>
>
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