[Dnsmasq-discuss] Mutliple Subnets - Different Servers - Chaining

richardvoigt at gmail.com richardvoigt at gmail.com
Wed Jul 14 00:55:56 BST 2010

On Tue, Jul 13, 2010 at 4:30 PM, Lord_Devi <lorddevi at gmail.com> wrote:
> I appologize the delay in my reply, but the past couple of days have
> been hectic ones for me. In response to Sergei Zhirikov's suggestion of
> using a dhcp relay agent on Subnet 1B, I think that is exactly the way
> to go! Indeed it was the first thing I looked at. However I was
> previously unaware of such functionality and had to wiki the definition.
> I then read what I could of course in the dnsmasq manpage, and googled
> for a while. However I find it easiest to learn from examples, and was
> not able to find any such examples. Just references and vague
> explainations on how to use it.
> Trying to setup a relay was beyond my ability.. even though it seemed to
> me the simplest explaination. If someone could provide me with an
> EXAMPLE of what a dnsmasq relay configuration might look like for my
> Subnet 1B in it's existing configuration there I would be endlessly
> grateful.

If you visit http://www.thekelleys.org.uk/ you will see that dnsmasq
is not a relay, but there is a separate program dhcp-helper from the
same author to act as a relay.

dnsmasq's dhcp server supports issuing addresses both directly and
indirectly (via a relay).  For direct dhcp, it will find the ip
address assigned to the interface where the request came in and give
out an address from a dhcp-pool in the same block (defined by the
subnet mask).  For indirect dhcp, the relay tells dnsmasq the address
of the interface where the request was received, all you have to do is
configure a dhcp-pool in the same block as the relay's interface which
faces toward the clients.

Hope this helps.

> In reply to both Brad Morgan and SamLT, I thank you both for your advice
> as well. However I am certain my routing tables are configured properly.
> The DD-WRT is set to route packets destined for through
> (The internal nick of the machine hosting
> And here is the important part: The virtual machines running on
> are currently getting a gateway of from my
> second dnsmasq machine running on the virtual hosts. In this
> configuration the packets are all going where they need to in a nice
> tidy manner. However in this lies one of my problems going back to the
> dhcp relay! If I were to configure my's dnsmasq to act as a
> relay agent, forwarding requests to my DD-WRT router, I would then need
> to instruct my DD-WRT's dnsmasq to give client requests from
> a Gateway of, and not like it
> gives to the rest of my network.
> I appreciate the advice on setting up my virtual machines to use bridged
> devices instead of host only. By the way, I AM using VMWare as well.
> (7.1 in fact). However for instructional purposes, I MUST configure
> things in such a way as to use Host only networking. Either NAT, or
> Bridging them is not an option. (Although I completely agree that it
> would simplify things greatly if I could.)
> Thank you, all of you, for your help and advice! I feel reassured I am
> on the right track being told to use a relay agent instead, as that is
> exactly what I had suspected.(It seems the simplest) Now if only I knew
> HOW that was done!!
> I love dnsmasq, but the documentation(what little there is) really needs
> more examples for us laymen to learn from! =)
> Have a good day all, Regards,
>   Casey Quibell (Lord_Devi)
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