[Dnsmasq-discuss] Client does not receive BOOTPREPLY

[Simon Kelley]

On 20/01/14 07:29, Roeland Douma wrote:
> Hi,
>
> I am setting up dnsmasq over at my parents but have an issue with 1
> client (a raspberry pi) not getting a response to his BOOTPREQUEST.
> All the other hosts (my laptop, my phone etc) all do get an valid lease
> so it seems something weird is happening.
>
> So a little more detail about the setup. There is the modem from the ISP
> (lets call it M) that just acts as a gateway. DHCP is turned off.
> Then there is the server (lets call it S) that runs a lot of stuff
> including dnsmasq.
> And then finally there is the client (let call it C). Now they are all
> connected via wired ethernet via a big switch.
>
> When C does a BOOTPREQUEST it does not get a response. However I see the
> BOOTPREQUEST appear on S and S does send a response.
>
>
> I tried to debug using dhcpdump and something weird does show. The
> BOOTPREQUEST on C looks normal. And in the IP part it nicely shows:
>
> IP: 0.0.0.0 (mac-of-C) > 255.255.255.255 (ff:ff:ff:ff:ff:ff)
>
> Also the correct MAC is displayed in the CHADDR field.
>
>
>
> When running dhcpdump on S it show the BOOTPREQUEST coming in:
>
> IP: 0.0.0.0 (mac-of-C) > 255.255.255.255 (ff:ff:ff:ff:ff:ff)
>
>
> which matches of course. But the BOOTPREPLY shows:
>
> 192.168.178.100 (mac-of-S) > 192.168.178.222 (mac-of-M)
>
>
> The CHADDR does match the mac-of-C
>
>
>
> I do not get why S wants to send the reply to M? Any idea's or
> suggestions on what to do next?
> I am running dnsmasq-2.66.
>

Look at the ARP table on S. I wonder if M is doing gratuitous ARPs?


Cheers,

Simon.

> Thanks in advance for any help.
>
> Cheers,
> --Roeland
>
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