[Dnsmasq-discuss] sometimes dhcp-script does not trigger on lease renewal

[Simon Kelley]

On 08/07/13 15:46, Stefan wrote:
> Hi list
>
> I'm using dnsmasq with openwrt, that's why i'm using v2.55
>
> I'm using the option --dhcp-script. normally the scripts triggers, if
> a host is getting this ip-address (new), is renewing or dnsmasq is
> restarting (old), a host is releasing it or lease is timing out (del).
> if dnsmasq is running for a certain time, renewing of certain hosts
> does not trigger the script and i don't know why.

If the expiry time of the lease doesn't change, then the script will not 
be run. It's possible that the client is asking for the remaining time 
to run on the lease when it "renews" rather than actually extending it. 
That would explain what you're seeing.

>
> I've run dnsmasq in no-daemon mode and with option --dhcp-log. the log
> didn't give me any hints. Do you have any??

Look in the dnsmasq lease file, the first field is the expiry time. If 
that doesn't change when the client renews, then that's the problem.



Thinks:

Does openWRT use the "Broken RTC" mode? I think it does. In that case, 
dnsmasq doesn't store the expiry time in the leasefile, it stores the 
lease length. That's much more likely not to change on a renewal. 
Essentailly, the script gets called when the lease database changes, and 
in Broken RTC mode, renewal doesn't change the lease database.



Cheers,

Simon.

>
> Greetz
> Stefan
>
>
>
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