[Dnsmasq-discuss] Problems with DHCP packets with broadcast flag enabled

[richardvoigt at gmail.com]

Check if sending the DHCPOFFER fails (if for example, it is a renewal
packet and therefore unicast rather than multicast, and it can't find
a MAC address for that client because ARP is blocked).  I think
checking the return value from `sendto` should trap this scenario.

If the DHCPOFFER packet doesn't make it to the interface, then the
client can't accept the offered address, and no entry will be made in
the lease table.

On Mon, May 7, 2012 at 2:47 PM, Daniel Figueira <danfig87 at gmail.com> wrote:
> Hello.
>
>
>
> I’m working on a scenario in which ARP is disabled on a given interface. We
> have a deamon that only responds to ARP requests coming from authorized
> clients. The authorized client list is given by the DHCP lease list.
>
>
>
> When emulating multiple DHCP clients with the Broadcast Flag active, the
> dnsmasq daemon receives the DHCP DISCOVER packets, and according to the log,
> it also sends the DHCP OFFER packets. However, when capturing traffic with
> tcpdump I am unable to see the DHCP OFFER packets. Furthermore, no DHCP
> leases exist in /var/lib/misc/dnsmasq.leases and no client gains IP.
>
>
>
> We are working in a Linux system (2.6.34.8).
>
>
>
> Do you have any suggestions to overcome this problem?
>
>
>
> Thanks in advance.
>
>
>
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