[Dnsmasq-discuss] dhcp-option=121 doesn't seem to work

Simon Kelley simon at thekelleys.org.uk
Thu Dec 20 21:17:53 GMT 2007


Guennadi Liakhovetski wrote:
> On Wed, 19 Dec 2007, Simon Kelley wrote:
> 
> 
>>Guennadi Liakhovetski wrote:
>>
>>>I also 
>>>added it to dnsmasq.conf like
>>>
>>>dhcp-option=<client-ip>,33,<target-network>,<gateway-ip>
>>>
>>Wrong syntax: you can't put the client-ip there. If you want to send
>>options to certain hosts only, you need to use tags. Sorry, should have
>>spotted that in your first message.
> 
> 
> Yep, thanks. But, as I said, it wasn't the problem with the option 121 - I 
> also tried without the restriction, just starting with 121.
> 
> Now, I did know 33 was deprecated, but as 121 doesn't seem to be supported 
> by the dhclient, and I didn't want to use extra scripts, I gave 33 a go. 
> Fixed the syntax, specifying like
> 
> dhcp-host=<mac>,net:<network-id>,<name>
> 
> dhcp-option=<network-id>,33,<network>,<router-ip>
> 
> and I do see this time in wireshark, that the option is sent from the 
> dnsmasq, but the route is not configured. Ok, this is now not dnsmasq's 
> problem any more, but maybe you would know, have they disabled "33" in 
> dhclient or why it doesn't work?

Basically, dhclient does everything via those scripts, so if there isn't 
shellcode in the script to take the information from option 33 or option 
121 and call "route" then it won't work.

> 
> 
>>>Do you know which dhcp client should support 121? I'm using dhclient ATM, 
>>>maybe it was dhcpcd that you meant? Or is it only supported in testing / 
>>>experimental Debian branches?
>>
>>dhcpcd doesn't support it, I think. dhclient can be made to, with
>>sufficiently clever scripting. See:
>>
>>http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2006q1/000621.html
>>
>>for the last time this came up.
> 
> 
> Wait, but you first have to request this option? I haven't managed even 
> that - haven't found its name.

Check the docs for dhclient - you can declare new option names if needed.


Cheers,

Simon.

> 
> Thanks
> Guennadi
> ---
> Guennadi Liakhovetski
> 




More information about the Dnsmasq-discuss mailing list