Milter-greylist

On 2013-05-19 11:37, Peter Bonivart wrote:
> But TTL is for the client to decide if it should refresh it's cache or
> not (use cache or ask server again), it doesn't mean the record will
> expire on the server which I believe is what manu means.

Hmm... I guess you're right. Still, it can be part of the expiration
mechanism - if the server has the blacklist entry removed by the time
of TTL re-request, the client would refresh its cache and see that
the target IP is no longer blacklisted.

I don't think there's a DNS notion of entry expiration. There's zone
expiration, which means that after some time that it has been cached
and couldn't be refreshed from source, it should no longer be trusted,
and queries via this cached data should begin to fail. This allows to
"put to rest" and discard unmaintained DNS zones which would otherwise
pollute the internet forever.

//Jim