cache server

[Brad Knowles]

At 3:11 PM -0700 7/12/01, sally wong wrote:

>  My understanding of the caching server is that if
>  caching server does not have the info, it will ask the
>  primary server or other server outside on the
>  internet, is this correct?

	Depending on how it is set up (whether it uses forwarding or 
not), a caching server will try to go find the answer on the 
Internet, if it does not have the answer in its local cache.  That's 
the entire idea.

>  I have noticed that our caching server does not always
>  notice the new DNS entries immediately.  It sometimes
>  picks up the entry immediately but sometimes not.
>  Sometime I have to wait some hours for the new entries
>  to be picked up by the caching server.

	Not surprising.  You've got old records that are cached, and 
therefore the caching server has no reason to try to go update them 
-- until they records time out.

>  Usually how long will it take the entry to take its
>  way to caching server?  It seems to me that eventually
>  the caching server picks up the new entries.  I do not
>  know how long it take, and where on the primary server
>  controls such variable?

	On average, it will take have the TTL of the changed record 
before the majority of servers detect the change.  If you want to 
propagate changes faster than this, you need to decrease your TTL to 
match.

-- 
Brad Knowles, <brad.knowles at skynet.be>

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