On 2016-03-24 09:50, Barry Margolin wrote:
The problem with this is that when the Office 365 records expire and are
removed from the cache, but the other records have not, the server will
not know that it should re-query for the O365 records. It still has TXT
records in its cache, and it will return them in response to a query.
It won't go back to the authoritative server until ALL the TXT records
expire. During the period between the short TTL and the longest TTL, it
will be as if the short-TTL records don't exist at all.
Or if a caching resolver did make a "note to self" that there are
missing records that need to be replaced, what would be the point of
keeping any records with a longer TTL? A resolver would still be sending
the same queries to refresh the entry with the shortest TTL anyway, so
it wouldn't reduce the query volume.
--
Dave Warren
http://www.hireahit.com/
http://ca.linkedin.com/in/davejwarren
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