question about authority

[Simon Waters]

Kristof Loots wrote:
> 
> I don't understand how can a name server be authoritative if the data is
> loaded from another name server?

Authority is a bit set on the answer. 

Any server that has complete information on a zone sets this bit
in an answer about data from that zone. How the server gets
complete information on a zone is totally irrelevant, it can
load it from a database, transfer it across the Internet, or
read it off carved stones handed down from above.

The only gotcha with authority (apart from old servers setting
the bit too often) is that if an error is detected in loading
the zone a server that is usually authoritative will decide that
it's information maybe incomplete and not send authoritative
answers. This is one way a server becomes lame.

Thus setting the authority bit is a 'trust me everything is
looking good that this is the right answer' style of response,
or a 'I am the right server to ask that question of'. 

Authority has nothing to do with delegation, although all
delegated servers must be authoritative.