refresh / expire

[Kevin Darcy]

bert hubert wrote:

> In article <a8siu7$ot4 at pub3.rc.vix.com>, those who know me have no need of
> my name wrote:
>
> ><a8g4bm$10d at pub3.rc.vix.com> divulged:
> >
> >>When we have a "refresh" rate, what is the purpose for an "expire" rate?
> >>Are the dns servers around the world not required to respect the refresh
> >>rate??
> >
> > only your secondary servers should respect either value.
>
> I was wondering, is there any valid reason for 'expire'? I've been bitten a
> few times by secondaries dropping a zone during prolonged outages. I'm not
> sure why I would ever want that to happen.

In my experience, many people set their EXPIRE values way too low. Probably
some novice admins are confused between TTL and EXPIRE. With a proper
EXPIRE setting, even a prolonged outage should never cause a zone to expire. I
set mine to more than a month. That's easily long enough to weather a
prolonged outage, but will at least cause obsolete data to go away eventually.


- Kevin