How to Increase the DNS Cache in Windows

The Domain Name System (DNS) makes it possible to assign domain names to groups of Internet users in a meaningful way, independent of each user’s physical location.

Because of this, World-Wide Web (WWW) hyperlinks and Internet contact information can remain consistent and constant even if the current Internet routing arrangements change or the participant uses a mobile device.

For example, when you type http://www.google.com into your web browser’s address bar, Windows sends a request to your service provider’s nameserver, and the nameserver responds with something like 74.125.45.100, and your browser can contact the web server and download the requested page.

Each time such a DNS (Domain Naming System) lookup is performed, the information is stored in the DNS cache so Windows doesn’t have to query the nameserver every time you access a page on that site.

A larger DNS cache will mean fewer trips to the nameserver and faster overall performance:

1. Open the Registry Editor

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2. Expand the branches to

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Dnscache\Parameters.

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3. Add the following four DWORD values by going to Edit > New > DWORD Value.

Enter the numeric values specified by doubleclicking and selecting the Decimal option:

• CacheHashTableBucketSize, set to 1
• CacheHashTableSize, set to 384
• MaxCacheEntryTtlLimit, set to 64000
• MaxSOACacheEntryTtlLimit, set to 301

Remember, these are Decimal values (not Hexadecimal values).

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4. Close the Registry Editor when you’re done. You’ll have to restart Windows
for this change to take effect.

Experiment with the values of the parameters above.  Just remember that the DNS cache is emptied when you shut down Windows, which is why it can take a little longer to find web sites just after you’ve booted up.

If  you want to put a permanent entry in the DNS cache, follow this tip we discussed earlier.

Ben Carigtan shows you how it’s done!

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