Interesting article on DNS cache tweaks

http://www.techiwarehouse.com/cms/engine.php?page_id=163e0b14

I had just yesterday contacted the authors of both CleanCache and Index.datSuite to see if an option could be added to have the dns cache flushed at every re-start - then I read this article this morning when trying to learn more about it.

The QueryIpMatching addition looked useful, too. Pete

 

The ability to flush the dns cache will be an option in the upcoming release of a new version of Index.dat Suite per Steven Burns email just received. Pete

 

Hi Spy,

That link doesn't seem to work for me, even though it appears to be correct after fetching it via a Google search cache !

Good news about the upcoming DNS clearout in a future Index.datSuite. Won't effect me or those on 98SE though. So you like my " better than sliced bread " phrase i see you posted on BBR lol.


StevieO

 

Stevie0 - For some reason, the link's not working here for me in FireFox - but it does work in IE (quoting appicable section):

"Configure the DNS Resolver Cache
A way to minimize problems from the long default wait times that are used for holding data in the DNS cache is to reduce the times (known as Time to Live or TTL). This requires a Registry edit so should be done only by those who know how to restore their Registry. The Registry key that is involved is
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DNSCache\Parameters

The binary entry MaxCacheEntryTtlLimit can be used to control how long positive responses are kept. Values are in seconds and the default value in the absence of an entry (the usual case) is 86,400 seconds or one day. If you wish to shorten the TTL, create the entry and enter your preferred time in seconds. Most PC users will probably not gain much this way, however.

Negative responses are another story. I often encounter Web sites that do not respond immediately but which are available after a short wait and a retry. A wait of five minutes would be neither convenient nor necessary. I see no reason to store negative responses in the DNS cache and I have tweaked my own Registry to prevent them from being entered. In this case create a binary entry for the above Registry key and name it NegativeCacheTime. Set the value to "0" (zero). If you prefer to keep the negative responses, but with a shorter TTL, enter the appropriate number of seconds. The default TTL is 300 seconds.

Defend Against Responses from Non-Queried Servers
If its settings are left alone, the DNS cache will also accept responses from servers that it never queried. In other words, Web sites that you never tried to reach could send a message looking like a response and it would be stored in the cache. This is a security hole that might allow unauthorized DNS servers to send invalid information for the purpose of misdirecting subsequent DNS queries.
Again a Registry edit is called for. To disable responses from sites that you never asked for, create a DWORD entry named QueryIpMatching . Put it in the same Registry key above and give it a value of 1."

Interesting stuff. (Not quite as good as sliced bread, however! ) Pete

 

I've been informed via PM that an alternate location for the QueryIpMatching registry key is:

HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Services \ Tcpip \ Parameters

I'll check mine here tomorrow, as I haven't done anything so far beyond reading the article. Good night, all. Pete

 

Could you use a batchfile to run at startup with "ipconfig /flushdns" ?

 

Franklin - Yes, I'm sure you could if you're knowledgeable about those kinds of things.

The "QueryIpMatching" key didn't exist in either of the locations noted

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DNSCache\Parameters
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters


above - so I put it in both locations. Everything's still working here. Pete

 

Does this involve the DNS Client service? Because some say it´s best to disable this service, just checking.

 

Source: HelpWithWindows, Technet.

 

If anyone's interested, the latest version of Index.dat Suite - 2.9.0 - http://support.it-mate.co.uk/?mode=Products&p=index.datsuite now enables "Delete Prefetch Folder Contents" . Pete