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Old January 1st 18, 04:45 AM posted to alt.windows7.general,microsoft.public.windowsxp.general
Mayayana
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Posts: 6,438
Default Windows DNS cache

"Brian Gregory" wrote

| I was wondering what all this talk was of Windows
| DNS Cache. I'd never heard of it. It should be clarified
| that "Windows DNS Cache" is actually the DNS Client
| service. It doesn't need to be enabled at all for most
| people. It's possible that people on a network with
| Active Directory may need it. I'm not familiar with
| that. I suspect they don't and that it will only save
| on a few intranet calls.
| I've had DNS Client disabled for years and see no
| reason to enable it.
|
| You don't need it if you LAN has it's own DNS cache but I guess it might
| be worth saving the 12MB of RAM it uses to save doing unnecessary DNS
| lookups over the Internet.
|
?? This post was close to 2 years old.

I don't have a LAN. I don't allow sharing with other
computers for security reasons.

If you look it up I think you'll find that the "time to live"
for these things is very brief, anyway. A day or less:

http://webcache.googleusercontent.co...&gbv=1&ct=clnk

Browsers can store their own cache. The default DNS
cache expiry in Firefox is 1 minute. The idea is not to
store a phone book but rather to save repeated DNS
requests for the same URL during a session.

If the cache were long-lived there would be problems
when a site changes IP address. I ran into that at one
point when I found that several sites had disappeared.
I finally figured out that the DNS proxy I use, Acrylic,
stores a much longer DNS stash. Something like 10 days.
Most of the time that's OK, but only if you know about
it and know to clear that cache if anything goes wrong.

Aside from that, I don't know of any reason to cache
DNS or to worry about cache. The storage time is brief
and the time required for a DNS query is negligible. So
it doesn't much matter one way or the other.



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