[Dnsmasq-discuss] ARP ignores DHCP ACKs !

[Jim Alles]

do you have dual-stack enabled on Win-7? Things are not all sorted out
with IPv6.

On Tue, Dec 24, 2013 at 2:49 PM, Nikita N. <nikitan at operamail.com> wrote:
> Hi Simon :)
> No, absolutely all happens after a nice shots of repeated DHCP reqs and
> ACKs.. I dumped a mess of traces here, Ill verify again, but anyway Im
> pretty sure about that.. as I said, the client "seems" to use the ip,
> but then it gives up..
> If can be useful, that happens only when client is Windows7.. when
> client is Linux, Win Xp or Vista, all goes nice.. im still trying more
> scenarios, but Im sure about that: im stuck on Win7..
>
>
> On Tue, Dec 24, 2013, at 11:22 AM, Simon Kelley wrote:
>> On 24/12/13 12:35, Nikita N. wrote:
>> > Hi :) Im having a strange issue here with DHCP/ARP I cant solve..
>> > DHCP works good, it receives a REQ from client MAC asking the preferred
>> > ip, e.g. 192.168.0.10, and DHCP answers correctly ACK..
>> > But after that, my client keeps asking the following ARP requests to
>> > broadcast: "Who has 192.168.0.10? Tell 0.0.0.0" .. it expects the answer
>> > like "192.168.0.10 is at XX.XX.XX.XX.XX", where XX is the client MAC..
>> > but it never comes :(
>>
>> Are you sure about the order of these events? Most DHCP clients will
>> check that the address they've been offered is not in use by anonther
>> machine before accepting it, and they do that by sending ICMP echo
>> requests. To send the echo request, the client's kernel will need to
>> send ARP requests and that probably what you are seeing.
>>
>> I'd expect to see the client sending these ARPs _afer_ the DHCPOFFER and
>> before the DHCPREQUEST.
>>
>>
>> Cheers,
>>
>> Simon.
>>
>> > those ARP frames are generated by the client (source=XX) and never
>> > receive any answer..
>> > on the opposite, when the client sends ARPs requesting the GW (Who has
>> > 192.168.0.1?) the ARP responses come correctly pointing to the correct
>> > GW MAC..
>> > It looks like dnsmasq does NOT inform the system ARP about the client ip
>> > it just ACKed, resulting always in connection error/absent ..
>> >
>> > So, my question is, how can I instruct dnsmasq to inform the system ARP
>> > with the new client MAC/ip, after DHCP sent correctly the ACK?
>> > Thanks :)
>> >
>>
>>
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