[dns-operations] resolver cache question
mallman at icir.org
Fri Nov 13 17:41:54 UTC 2020
I just finished reading a paper that basically tries to figure out
if a hostname is worth caching or not . This isn't the first
paper like this I have read. This sort of thing strikes me as a
solution in search of a problem. The basic idea is that there are
lots of hostnames that are automatically generated---for various
reasons---and only ever looked up one time. Then there is an
argument made that these obviously clog up resolver caches.
Therefore, if we can train a fancy ML classifier well enough to
predict these hostnames are ephemeral and will only be resolved the
once---because they are automatically generated and so have some
tells---then we can save cache space (and effort) by not caching
- My first reaction to the notion of clogging the cache is always
to think that surely some pretty simple LFU/LRU eviction policy
could handle this pretty readily. But, that aside...
- I wonder how much this notion of caches getting clogged up
really happens. Could anyone help with a clue? How often do
resolvers evict entries before the TTL expires? Or, how much
over-provisioning of resolvers happens to accommodate such
records? I know resolver caching helps , but I always feel
like I really know nothing about it when I read papers like
this. Can folks help? Or, point me at handy references?
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