Cacheing Issue?

Re: Cacheing Issue?

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At 4:26 PM -0500 9/6/01, Derrick Fogle wrote:
>I'm currently running QDNS 2.2.1 on 2 Macs running 9.0.4 (master and slave).
>
>For computers configured to use our DNS servers, there are a few
>sites that never get found on first query. One of those sites is
>quote.yahoo.com. The first time a browser tries to load the site,
>there's some error (usually "the specified server could not be
>found"); but I can almost instantly load the site a second time, and
>it always comes up.
>
>Anyone know why? Can I fix it with what I've got?

The reason is, Yahoo has decided to make your DNS server jump through
several hoops to find the address for that name. It takes more than
the amount of time that your browser is willing to wait, but it does
find the answer eventually. Then, when you it the reload button, your
DNS server already has the address in cache.

Here's what QuickDNS has to do (assuming it has nothing cached) to
look up this name:

- Ask a root server, which gives a list of com servers.
- Ask a com server, which gives a list of yahoo.com servers.
- Ask a yahoo.com server, which gives the following response:

quote.yahoo.com. CNAME finance.yahoo.com.
finance.yahoo.com. CNAME finance.yahoo.akadns.net.

- Go back to start. Ask a root server, which gives a list of net servers.
- Ask a net server, which gives a list of akadns.net servers.
- Ask one of the Akamai servers, which gives the final answer:

finance.yahoo.akadns.net. A 216.115.107.7
finance.yahoo.akadns.net. A 216.115.106.7

All of this may take less than a second, or it may take several
seconds. It all depends on the response times of the various servers
queried. Your browser probably only waits 7.5 seconds.
____________________________________________________________________
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cbuxton@menandmice.com We Make DNS Easy!

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