[Dnsmasq-discuss] DHCP Request Flood

Gavin Hill gavin at highpeak.co.za
Wed Feb 25 09:14:42 GMT 2015


As a quick update, I tried changing 

dhcp-range=192.168.1.1,192.168.1.99,static,48h

to

dhcp-range=192.168.1.1,192.168.1.99,static,infinite

Things slowed down a little and I’m seeing fewer log entries, but it still doesn’t explain why the 48h entry didn’t seem to work.  I’m assuming 48h is a valid syntax?


> On 24 Feb 2015, at 10:31 AM, Gavin Hill <gavin at highpeak.co.za> wrote:
> 
> I’m using dnsmasq on a Raspberry Pi as a DHCP and DNS server for my home network.  I switched to using the Pi as it boots fast and dnsmasq can start handing out IP addresses on my network quickly after a power failure (IP cameras, alarms system, etc).
>  
> Network: 192.168.1.0/24
> Range 1-99 static, defined in /etc/dnsmasq.d/reservations file
> Range 100-250 dynamic
>  
> If I check my syslog though, I see many of my static devices requesting IP addresses every 60 seconds or so, suggesting their leases are only 120 seconds.  I’ve searched for the issue but the only hits I could find were related to windows machines looking for and autoconfig option (option 252).  While I’ve added that option, many of the requests are not coming from Windows machines anyway.
>  
> dhcp-range=tag:!known,192.168.1.100,192.168.1.250,12h             #Dynamic devices
> dhcp-range=192.168.1.1,192.168.1.99,static,48h                                #Static devices in /etc/dnsmasq.d/reservations e.g. dhcp-host=00:0c:5d:dc:4f:3c,192.168.1.52,cctv-ptz
>  
>  
> Feb 24 10:15:13 ipam dnsmasq-dhcp[23224]: DHCPREQUEST(eth0) 192.168.1.52 00:0c:5d:dc:4f:3c
> Feb 24 10:15:13 ipam dnsmasq-dhcp[23224]: DHCPACK(eth0) 192.168.1.52 00:0c:5d:dc:4f:3c cctv-ptz
> [may repetitive entries removed]
> Feb 24 10:16:10 ipam dnsmasq-dhcp[23224]: DHCPACK(eth0) 192.168.1.52 00:0c:5d:dc:4f:3c cctv-ptz
> Feb 24 10:16:14 ipam dnsmasq-dhcp[23224]: DHCPREQUEST(eth0) 192.168.1.21 00:20:4a:a8:28:fe
>  
>  
> Regards
> Gavin
>  
> --
> Gavin Hill – gavin at highpeak.co.za <mailto:gavin at highpeak.co.za> – http://www.highpeak.co.za <http://www.highpeak.co.za/> -- @HighpeakHA  
>  
> 
> 
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