WinXP won't clear the DNS cache (can it be cleared manually)?
in [Wireless Internet]
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From: Dave Warren on 28 Mar 2010 18:27 In message <hola76$j43$1(a)tioat.net> Kat Rabun <katspianostudioXXX(a)Use-Author-Supplied-Address.invalid> was claimed to have wrote: >On Sat, 27 Mar 2010 15:33:01 +0000 (UTC), Kat Rabun wrote: > >> What does the DNS Client actually do (besides preventing a network repair)? > >For my type of home network, the DNS Client service doesn't appear to do >anything useful! :( > >I have a giant hosts file which I update daily as I run into web sites I >feel act suspiciously (malware, javaware, flashware, annoying popups, >etc.). I also remove duplicate entries programatically (unixutils "sort >-u"). > >In my home network, all the Windows XP SP3 DNS Client seems to (really) do >is just two bad things: >- The DNS Client prevent network repairs (by preventing DNS flushes) >- The DNS Client foul ups systems with large hosts files > >Apparently the DNS Client service optimizes the performance of DNS name >resolution by storing previously resolved names in memory. If the DNS >Client service is turned off, the computer can still resolve DNS names by >using the upstream DNS servers. DNS Client also caches the contents of the HOSTS file, otherwise every single DNS lookup goes through the file line by line looking for comparisons. If you have local, fast, reliable DNS servers and a trivial HOSTS file, DNS Client adds little benefit. However, if you have a large HOSTS file, DNS Client speeds up lookups significantly. Similarly, if you have unreliable DNS servers, or your DNS servers are more than a few milliseconds away, DNS Client can create a significantly snappier user experience.
From: Harry331 on 28 Mar 2010 21:50 Kat Rabun wrote... > >In WinXP SP3 "Network Connections", I right click "Repair" the wired "Local >Area Connection" but always get an error. How do I clear the DNS cache? > >Here is the error I always get (even after rebooting): > > Repair Local Area Connection > Windows could not finish repairing the problem because the > following action cannot be completed: > Clearing the DNS cache > For assistance, contact the person who manages your network. > >Unfortunately, I am the person who "manages" the home network. > >How do I repair an Internet connection that won't release the dns cache? >(I have a similar problem with the wireless connection which it won't >release) Not sure if the following help. c:\> ipconfig /flushdns Windows IP Configuration Successfully flushed the DNS Resolver Cache. c:\>
From: Ace Fekay [MVP-DS, MCT] on 29 Mar 2010 01:20 "Kat Rabun" <katspianostudioXXX(a)Use-Author-Supplied-Address.invalid> wrote in message news:hom71v$qp9$1(a)tioat.net... > On Sat, 27 Mar 2010 14:35:18 -0500, Char Jackson wrote: > >> My question would be, what problem are you having that is causing you >> to try to repair the connection? > > Every once in a while (maybe once a week or once every few weeks or so), > the wireless Internet connection goes "down" on the PC. > > When I "repair" it, it comes back "up". > > I don't really know more than that ... but I've found now that setting the > DNS Client to "manual" is what caused the wireless connection to not be > able to be repaired. It repairs now that I've started the DNS Client > manually. > > I wonder whether most people follow the recommendation to disable > unnecessary services such as the "DNS Client"? Where did you get that recommendation from? And based on where you got it from, what was the recommendation based on? Were you having a resolution problem, or infected with a virus that was affecting the resolver algorithm? -- Ace This posting is provided "AS-IS" with no warranties or guarantees and confers no rights. Please reply back to the newsgroup or forum for collaboration benefit among responding engineers, and to help others benefit from your resolution. Ace Fekay, MVP, MCT, MCITP EA, MCTS Windows 2008 & Exchange 2007, MCSE & MCSA 2003/2000, MCSA Messaging 2003 Microsoft Certified Trainer Microsoft MVP - Directory Services If you feel this is an urgent issue and require immediate assistance, please contact Microsoft PSS directly. Please check http://support.microsoft.com for regional support phone numbers.
From: Kat Rabun on 29 Mar 2010 03:49 On Mon, 29 Mar 2010 01:20:00 -0400, Ace Fekay [MVP-DS, MCT] wrote: >> I wonder whether most people follow the recommendation to disable >> unnecessary services such as the "DNS Client"? > Where did you get that recommendation from? Everywhere I looked, people strongly advise disabling DNS caching! "The most important thing to do before using large HOSTS files is to disable the DNS Client" http://www.ericphelps.com/scripting/samples/Hosts/index.htm "We recommend disabling the "DNS Client" service on all local computers" http://www.simpledns.com/kb.aspx?kbid=1089 "Turn off the "DNS Client" service entirely. This is What we are recommending!" http://grandcountyinternet.com/DNSResolverCache/ "To avoid the slowdown, either disable the DNS Client or avoid using a large HOSTS file" http://smallvoid.com/article/winnt-services-dnscache.html "Disable caching of unsuccessful ("negative") DNS lookups" http://forums.mozillazine.org/viewtopic.php?t=5501 "Unless you are accessing network filesystems and databases, disable the DNS Client" http://www.jasonn.com/turning_off_unnecessary_services_on_windows_xp etc. Even Microsoft weighs in, albeit not as strongly as the rest of the world! "DNS caching ... may generate a false impression that DNS "round robin" http://support.microsoft.com/kb/318803
From: Char Jackson on 29 Mar 2010 05:57
On Mon, 29 Mar 2010 07:49:18 +0000 (UTC), Kat Rabun <katspianostudioXXX(a)Use-Author-Supplied-Address.invalid> wrote: >On Mon, 29 Mar 2010 01:20:00 -0400, Ace Fekay [MVP-DS, MCT] wrote: > >>> I wonder whether most people follow the recommendation to disable >>> unnecessary services such as the "DNS Client"? >> Where did you get that recommendation from? > >Everywhere I looked, people strongly advise disabling DNS caching! That's strange, do any of the links you provided actually recommend disabling DNS caching? They don't seem to be recommending that at all. >"The most important thing to do before using large HOSTS files is to >disable the DNS Client" >http://www.ericphelps.com/scripting/samples/Hosts/index.htm So don't use a large Hosts file. Problem solved. (I didn't check this link.) >"We recommend disabling the "DNS Client" service on all local computers" >http://www.simpledns.com/kb.aspx?kbid=1089 This advice only applies if you're running their DNS Plus application. >"Turn off the "DNS Client" service entirely. This is What we are >recommending!" >http://grandcountyinternet.com/DNSResolverCache/ Two problems with this one. First, it's from 2002, and second, and even more importantly, it's from John Navas. I wouldn't take advice from John Navas. >"To avoid the slowdown, either disable the DNS Client or avoid using a >large HOSTS file" >http://smallvoid.com/article/winnt-services-dnscache.html So don't use a large Hosts file. Problem solved. (I didn't check this link.) >"Disable caching of unsuccessful ("negative") DNS lookups" >http://forums.mozillazine.org/viewtopic.php?t=5501 This seems to be a user forum where a couple of folks are reporting a gut reaction that doesn't seem to be supported by any facts; i.e., disabling the DNS Client service dramatically increases page rendering time. Extremely doubtful, especially without any benchmarks to back up the claims. >"Unless you are accessing network filesystems and databases, disable the >DNS Client" >http://www.jasonn.com/turning_off_unnecessary_services_on_windows_xp The comment from this page is "Comment: It's typically good to leave this on.". >etc. > >Even Microsoft weighs in, albeit not as strongly as the rest of the world! > >"DNS caching ... may generate a false impression that DNS "round robin" >http://support.microsoft.com/kb/318803 Last but not least, this KB article doesn't make any kind of blanket recommendation about disabling the DNS Client service. In summary, I don't see any reason to disable it at all. |