Wildly excessive DHCPREQUESTs

Benjamin Wiechman benw at meltel.com
Wed Feb 20 16:57:20 UTC 2008

I have seen this with many different brands of routers: Linsys, Belkin
(seemed to be the worst culprit to me), Netgear. We have seen it after some
bad electrical storms across our network. 

It can be a real PITA. I've seen upwards of 20k requests from several
devices. I have noticed that a restart of the dhcp process can sometimes
help if there are multiple devices that are pounding the server. On routers
an update/reflash of the firmware, or sometimes simply a power cycle seems
to help as well. 

Ben Wiechman

> -----Original Message-----
> From: dhcp-users-bounce at isc.org [mailto:dhcp-users-bounce at isc.org] On
> Behalf Of Scott Baker
> Sent: Tuesday, February 19, 2008 4:47 PM
> To: dhcp-users at isc.org
> Subject: Re: Wildly excessive DHCPREQUESTs
> David W. Hankins wrote:
> > On Tue, Feb 19, 2008 at 04:12:44PM -0600, John Hascall wrote:
> >> about 11,000/day.  Does anyone have any idea what might make a
> >> box do a DHCPREQUEST/ACK cycle about every five seconds all day,
> >> day after day (despite getting a 4 day lease)?
> >
> > I've seen something similar with...of all things...Nintendo Wii's.
> > When they're suspended but have 'connect24' enabled, they seem to
> > reconfirm network attachment with a DHCPREQUEST inbetween brief sleep
> > cycles (7-20 minutes).
> >
> > My intuition would be to see if the client is having its interface
> > state cycled rapidly like that; many clients will attempt a request
> > to confirm they haven't changed networks.
> We see "broken" routers that re-request DHCP just like you describe.
> For whatever reason, we see to seem this most often with Netgear
> routers. It's certainly not ONLY Netgear though.
> --
> Scott Baker - Canby Telcom
> RHCE - System Administrator - 503.266.8253

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