[Pdns-users] Remote Backend SOA Response

Wieger Opmeer pdns at a6502.net
Sat Feb 23 11:31:13 UTC 2019


Hi Chris,

Adding my 2cts:


On Sat, 23 Feb 2019, bert hubert wrote:

> On Sat, Feb 23, 2019 at 08:12:40PM +1100, Chris Jones wrote:
>> Thanks Bert, but I don’t understand how my backend is doing too much work?
>> How does PowerDNS know what the zone is if my backend doesn’t figure it out?
>
> Chris, please carefully read the blog post. It is in there.
>
> "The PacketHandler can send many kinds of questions depending on the nature
> of your zone.  For example, it may ask about SOA records, even for zones you
> do not host in your backend.  This is because when a question comes in for
> ‘www.something.com’, PowerDNS must go hunt for a backend with relevant
> data."


What might help your understanding of what the backend should do is to 
look at the kind of queries the various sql backends make to the database. 
Set up a zone using a mysql or postgresql backend and enable query logging 
on the *sql server, now do some dns queries using dig and look at the 
querty pattern in the query log.

Basically the backend should be rather 'dumb' and just answer the 
exact questions that pdns asks: on a SOA query for 
'sdfsdf.sdf.kjhkjh.domain.net' reply with 'not here'. Pdns will then do a 
soa query for 'sdf.kjhkjh.domain.net' and continue walking up the tree 
until it finds something or runs out of tree.


~~
   Wieger Opmeer

-- 
There's no time like Guinness time..


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