[Dnsmasq-discuss] DNSMasq script lookup

[Simon Kelley]

On 29/03/12 12:52, Rance Hall wrote:
> On Thu, Mar 29, 2012 at 3:54 AM, Simon Kelley<simon at thekelleys.org.uk>  wrote:
>
> <snip>
>
>
>> On thing which might be interesting, is to define a new type of upstream
>> server (maybe called a look-aside server) which dnsmasq will send a query to
>> first, and which if it can't answer the query can return a custom
>> return-code "Not known", which causes dnsmasq to then push the query into
>> the standard server pathway.
>>
>> That becomes useful if such a server exists.
>>
>>
>> Cheers,
>>
>> Simon.
>
> Simon:
>
> I just wanted to chime in here because this idea would fix one of the
> problems I've been working with for some time.
>
> I have my own dns server (to deal with IPs that send my mail server spam, etc)
>
> I currently send all dns requests to my dns server first.
>
> The second dns server is fast (its a small install of djbdns from Dan
> Bernstein).
>
> But not every query needs to be handled this way.
>
> I could improve the overall efficiency if of this idea if I could
> somehow filter which dns queries go off toward my server and which go
> out to the internet the standard way.
>
> Your "look-aside" server idea would go a long way toward making this
> happen.  The only missing piece would be a sensible way to choose if
> the look-aside server was needed or not.
>

That's sort of backwards from what I was envisaging. The point of the 
look-aside server is that it sees _all_ the requests but only chooses to 
answer some of them.

You can route just a subset of queries to a local server using dnsmasq 
now, as long as the criteria for choosing which is just the domain.
Other filters could be added, but I can't think off-hand of any other 
useful ones.


Simon.