Re: DNS Round Robin

[Florian Weimer <fw () deneb enyo de>]

> My theory is as follows.  The query causes the caching NS to get the two 
> answers but the software stores them in numerical order.  The default 
> for bind is to "round-robin" so it choses the first (and thus the lower 
> IP address) as the first value.  Since the TTL is zero, the software 
> then discards the data so it never gets to select the second value in 
> its robin robin scheme.
>
> Does this sound plausible?

It's plausible.  I would assume this behavior without looking at the
source code, too.

> Has anyone else observed this?  Is it a bug or a feature?

It's a feature.  Anything which discourages the use of TTL 0 is a
feature.