[Dnsmasq-discuss] DNSMasq script lookup

[Simon Kelley]

On 29/03/12 20:12, richardvoigt at gmail.com wrote:
>
> 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.
>
>
> How's this help?  Hasn't dnsmasq thrown away the information it would
>  need to send the query to a second server at this point?

The look-aside server speaks the DNS protocol, which implies that the
"Not known" reply includes the original query, giving dnsmasq the
information is needs to send the query on.

We're giving the look-aside responsibility for storing in-flight 
queries, which makes some sense, since if its talking to a database or 
similar, it is presumably fairy heavy-weight.

>
> Or is the fingerprint kept in a "not known" table, such that when the
>  client tries again (and dnsmasq receives a second copy of the
> query), the look-aside is skipped and the normal servers are used?
> That would work, but add a non-negligible retry timeout to all
> queries which use the normal servers.

That's not the proposal, for the reason you give.


Cheers,

Simon.