On 27/09/18 20:24, gravit...@gmx.com wrote:
> Hi Simon,
> thank you for your answer.
> I confirm no --dhcp-broadcast option.
>  
> I dont really want to bother too much... but if you could just give me a
> couple of examples of that last thing.
> I mean, could you just give me a simple example of "hardware address
> length field is zero or greater than 16"?
> And/or a simple example of "hardware address type field is zero."?
> We talking about the <mac dongle>?
> Or, how can I check on Linux the "hardware address length field" and
> "hardware address type"?
>  


In the DHCPDISCOVER packet, these are bytes 2 and 3. Byte 1 is 1
(BOOTREQUEST) and byte 2 is the "hardware address type", whilst byte
three is the "hardware address length", which is typically 6 for what
people normally think of as MAC addresses.


Cheers,

Simon.

> After that I promise I wont bother anymore ;)
> Thanks
>  
> *Sent:* Wednesday, September 26, 2018 at 4:36 PM
> *From:* "Simon Kelley" <si...@thekelleys.org.uk>
> *To:* dnsmasq-discuss@lists.thekelleys.org.uk
> *Subject:* Re: [Dnsmasq-discuss] No Broadcast Dhcp Offers
> On 26/09/18 17:33, Simon Kelley wrote:
>> On 24/09/18 11:45, gravit...@gmx.com wrote:
>>>
>>> Amof, the first and only frames my dongle sends on eth at start, are
>>> some Dhcp DISCOVER, no arps at all.
>>> Please note that such Dhcp DISCOVER frames come with the broadcast bit
>>> NOT set.
>>> Afaik, that meas my dongle is indeed asking the Dhcp server to send a
>>> unicast response, directly to its mac.
>>> Instead QNSMASQ sends those Dhcp OFFER frames to broadcast.
>>> Why it happens so?
>>>  
>>
>> I can offer two reasons why it might be so. The first is that there's a
>> bug in dnsmasq, which is not unheard-of, but this is old code and a bug
>> has not been observed before. The second is that you're running dnsmasq
>> configured to always send broadcasts, using the --dhcp-broadcast option.
>>
>> Check all the dnsmasq configuration files, that's the sort of thing that
>> gets slipped in because is solves someone's problem one time, and "it
>> can't do any harm".
>>
>>
> 
> Looking at the code, it also falls back to broadcast if the "hardware
> address length field is zero or greater than 16, or if the "hardware
> address type" field is zero.
> 
> 
> Cheers,
> 
> Simon.
> 
> 
> _______________________________________________
> Dnsmasq-discuss mailing list
> Dnsmasq-discuss@lists.thekelleys.org.uk
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