DNS cache not working?



  • I was trying to see if the DNS forwarder would shorten the turn-around time on DNS resolution, so I turned on the forwarder and set my DNS to look at the opendns servers (and unchecked the overwrite). Then I did a Diagnostics>DNSLookup to google.com, etc.

    The first time 127.0.0.1 took 95ms or so but the second time it went to zero, which suggests the cache is working. But if I go back a few minutes later the lookup is back to 95ms or whatever, as if the cache is cleared right away. Seems like the cache should hang around longer than a few minutes.

    I am running 2.1 beta i386, the 03/31 snapshot.

    <later>Oh, one other thing. Is there some way to look at the cached values in tabular form? I looked around but couldn't find anything…</later>



  • The cache is retained for the length of the TTL of the hostname you're looking up. That'll be anywhere from 1 second to 1 day depending. Google is 5 minutes.



  • Wow, that's shorter than I imagined. Thanks for responding…


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