[Dnsmasq-discuss] CNAME

[Simon Kelley]

Merlin wrote:
> Hi, Simon,
> 
> Thanks for the detailed explanation. I think I understand now!
> 
> But would it not be possible achieve roughly the same functionality 
> within the dnsmasq architecture (without using CNAMEs) if there were 
> some sort of configuration option that says a lookup of "foo" should 
> always be proxied to the upstream server(s) as a lookup of "bar" 
> instead? (Kind of a name based version of the --alias option instead of 
> the current IP based version?)
> 
> Merlin
> 

Doing that suffers from the same sort of problems: It would  be easy to 
re-write the query as "bar" instead of "foo", but then the answer would 
come back as "bar is 1.2.3.4" Sending that answer back to the original 
requestor will get you nowhere: it asked for the A record for "foo" and 
will ignore an answer for "bar". So the re-write would have be reversed 
on the way back throught dnsmasq. That means keeping re-write 
information for all in-progress queries. That changes the current 
datastructure for in-progress queries from a fixed-size table mapping 
query-id to original source into a dynamically allocated monster with 
large records. By now you're re-writing BIND.

Cheers,

Simon.