caching DNS TTL ...question

[Barry Margolin]

In article <aa9aen$ar0 at pub3.rc.vix.com>,
Peter Sands <peter_sands at techemail.com> wrote:
>
>Hello,
>
>Can someone explain the use of the TTL (localhost.rev) in a caching
>DNS.
>I know ( understand), that when a initial query is made, the caching
>dns goes off to the root servers/DNS, resolves the query and sticks it
>into the local cache. Also attached to this is the TTL from the
>server, to say how long before the resolved query is considered stale.
>Now does the TTL in the localhost.rev file then checks its cached
>queries and compares the localhost.rev TTL against the cached
>query/TTL ???, to decided when it needs to go off again to extract
>that query.

The TTL in localhost.rev is the TTL to include in answers when someone
queries your server for the reverse DNS of 127.0.0.1.  It has nothing to do
with your server's caching.  When your server caches an answer, it uses the
TTL that the remote server sent back to it.

-- 
Barry Margolin, barmar at genuity.net
Genuity, Woburn, MA
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