[Dnsmasq-discuss] DHCP options, in particular setting default route

Chris G cl at isbd.net
Fri Aug 21 10:13:28 BST 2009


On Thu, Aug 20, 2009 at 10:09:46PM -0700, JD wrote:
> 
> 
> On 08/20/2009 05:32 PM, Carlos Carvalho wrote:
> > JD (jd1008 at gmail.com) wrote on 20 August 2009 15:01:
> >   >
> >   >On 08/20/2009 02:43 PM, Carlos Carvalho wrote:
> >   >>  Chris G (cl at isbd.net) wrote on 14 August 2009 11:03:
> >   >>    >I'm pretty sure dnsmasq can do what I want but I'd just like to
> >   >>    >confirm the details of how to do it.
> >   >>    >
> >   >>    >I want dnsmasq to set default routes for DHCP clients, so I need to
> >   >>    >use --dhcp-option, so far so good.  However the extra bit I'm not
> >   >>    >quite clear about is that I want to set different default routes for
> >   >>    >different clients.
> >   >>    >
> >   >>    >So I need something like:-
> >   >>    >
> >   >>    >      --dhcp-option =<network id>,option:router, 192.168.1.1
> >   >>    >
> >   >>    >for each client (or list of clients given by the network id) that
> >   >>    >needs to use default route 192.168.1.1.
> >   >>    >
> >   >>    >What I'm not quite clear about is what the network id looks like
> >   >>    >and/or if I need to set it myself using other dnsmasq arguments.
> >   >>
> >   >>  You have to give the netid for the machine in the dhcp-host declaration.
> >   >>
> >   >>
> >   >The network ID can be the MAC address of the machine.
> >
> > I'm not sure what you mean. The net-id can be set to the mac yes, but
> > I think it must be done explicitly in the dhcp-host declaration; the
> > manual doesn't say it defaults to the mac if omitted. I'd rather use
> > something easier to recognize; here I set it to the hostname.
> Well and good - I assumed Chris already knew
> "it must be done explicitly in the dhcp-host declaration".
> 
No I didn't, it was some of what I was asking as it wasn't clear (to
me amnyway) what a network ID was.  At first glance it *could* have
been the system's host name.

> Also, I did not say it cannot be something like the hostname -
> I only stated what it can be, and not what it MUST be.
> 

Thanks to you both I think I now know that the Network ID is an
arbitrary name that *I* give to a system and which can then be used in
other DHCP options (and elsewhere maybe).

-- 
Chris Green




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