[Dnsmasq-discuss] OpenWrt - dnsmasq - debugging delayed responses

[Geert Stappers]

On Thu, Jul 16, 2020 at 08:53:50AM -0400, Daryl Richards wrote:
> On 2020-07-15 9:13 p.m., Arseny Vakhrushev wrote:
> > Hello all,
> > 
> > I'm trying to debug delayed DHCP responses in OpenWrt 19.07.3. The
> > machine is connected to the router via Ethernet to eliminate possible
> > network latency and packet loss.
> > 
> > I tried playing with the debugging options of dnsmasq as well as
> > with all the DHCP related options including dhcp-reply-delay with
> > no apparent success.
> 
> You might have tried this, but you didn't explicitly mention it:
> 
> -5, --no-ping
>     (IPv4 only) By default, the DHCP server will attempt to ensure that an
>     address is not in use before allocating it to a host. It does this by
>     sending an ICMP echo request (aka "ping") to the address in question. If it
>     gets a reply, then the address must already be in use, and another is tried.
>     This flag disables this check. Use with caution.
> 

A network sniff  (tcpdump, tshark, wireshark) will provide information
about it.



Regards
Geert Stappers
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