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Re: Bind: A caching local server caches but not for long

From Michael Stone <mstone@debian.org>
Newsgroups linux.debian.user
Subject Re: Bind: A caching local server caches but not for long
Date 2018-09-17 13:30 +0200
Message-ID <wyZT3-5dw-7@gated-at.bofh.it> (permalink)
References <wyNId-6wn-1@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On Mon, Sep 17, 2018 at 12:20:51AM +0200, local10 wrote:
>;; ANSWER SECTION:
>old.reddit.com.         241     IN      CNAME   reddit.map.fastly.net.
>reddit.map.fastly.net.  8       IN      A       151.101.21.140

this number              ^^^
is the TTL/"time to live" in seconds. It is set by the server 
distributing the records and is typically set to something fairly long, 
like a day or more, for domains which don't change much. For domains 
which do change often, or if a move is planned in the near future, the 
TTL may be set low so that old records aren't cached long after they're 
obsolete. In this case the TTL in your cache shows 241 seconds left for 
old.reddit.com and 8 seconds remaining for reddit.map.fastly.net. By 
checking the authoritative nameservers directly it seems that the former 
is never more than 5 minutes while the latter is set to only 30 seconds. 
So your caching server should be updating fairly often.

Mike Stone

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Thread

Bind: A caching local server caches but not for long local10 <local10@tutanota.com> - 2018-09-17 00:30 +0200
  Re: Bind: A caching local server caches but not for long Pascal Hambourg <pascal@plouf.fr.eu.org> - 2018-09-17 00:50 +0200
    [SOLVED] Re: Bind: A caching local server caches but not for long local10 <local10@tutanota.com> - 2018-09-20 22:20 +0200
  Re: Bind: A caching local server caches but not for long Michael Stone <mstone@debian.org> - 2018-09-17 13:30 +0200

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