Constant DHCP requests...

Jason Gerfen jason.gerfen at gmail.com
Tue Aug 2 16:01:47 UTC 2011


I don't recommend disconnecting each port if your users are working,
eliminating the possibility of a client broadcasting the req/ack
packets you have been capturing is another route to take if the
manufacturer is indicating they have not found any problems on their
end.

On Tue, Aug 2, 2011 at 9:55 AM, Jeff Justice
<listaccount at starionline.com> wrote:
> No logging that I can find other than WireShark.  The router is the dhcp server.
>
> "Try disconnecting each port on the router to find the culprit?"
>
> Are you suggesting that another device on the network could be causing the problem?  I already know if I disconnect the device I mentioned in my initial post, it stops.  What I'm trying to get to here is some kind of proof that I can give to the manufacturer of a problem with their firmware.
>
> They say they have reviewed it several times and found no problems, so I want to see if I can give them more technical information about what to look for.
>
> Jeff
>
>
> On Aug 1, 2011, at 8:42 PM, Jason Gerfen wrote:
>
>> It sounds like a broadcast storm. Any logging from the router or even
>> the dhcp server? Maybe a client is broadcasting? Try disconnecting
>> each port on the router to find the culprit?
>>
>> On Mon, Aug 1, 2011 at 7:36 PM, Frank Bulk <frnkblk at iname.com> wrote:
>>> What device is this?  We continue to see issues with Belkin routers in our
>>> SP network.  A firmware upgrade usually resolves the issue.
>>>
>>> Frank
>>>
>>> -----Original Message-----
>>> From: dhcp-users-bounces+frnkblk=iname.com at lists.isc.org
>>> [mailto:dhcp-users-bounces+frnkblk=iname.com at lists.isc.org] On Behalf Of
>>> Jeff Justice
>>> Sent: Sunday, July 31, 2011 7:52 AM
>>> To: Users of ISC DHCP
>>> Subject: Constant DHCP requests...
>>>
>>> I know this list is for the ISC DHCP, but I am having a DHCP problem that I
>>> was hoping someone could shed some light on.
>>>
>>> I have a device that hooks to our network that gets its address via DHCP.
>>> When it is first powered on, it sits there for anywhere from 5 to 20 minutes
>>> without a problem, but then the network light starts flashing constantly.
>>>
>>> I ran a Wireshark trace and discovered that I was getting a constant stream
>>> of DHCP Requests from the device followed by the router sending an ACK.
>>>
>>> What led me to ISC's DHCP was that I thought I would install it on a server
>>> on our network, turn off our router's DHCP to see if the problem changed.
>>> It didn't.  I am still getting flooded with the DHCP request/ack.
>>>
>>> I have had a conversation with the device manufacturer who says they can't
>>> find any problems with their device.  They sent me a replacement which has
>>> the same problem.
>>>
>>> This leads me to believe that there is something in the programming of the
>>> device that isn't handling the DHCP server's response correctly, or there is
>>> a problem with my network or maybe even a switch?
>>>
>>> I'm not sure what steps to take at this point to solve this.  I can't put
>>> the device in production until I have figured out the cause.
>>>
>>> Any ideas?
>>>
>>> Jeff
>>> _______________________________________________
>>> dhcp-users mailing list
>>> dhcp-users at lists.isc.org
>>> https://lists.isc.org/mailman/listinfo/dhcp-users
>>>
>>> _______________________________________________
>>> dhcp-users mailing list
>>> dhcp-users at lists.isc.org
>>> https://lists.isc.org/mailman/listinfo/dhcp-users
>>>
>>
>>
>>
>> --
>> Jas
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>>
>
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>



-- 
Jas



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