Re: WinXP won't clear the DNS cache (can it be cleared manually)?

On Sat, 27 Mar 2010 15:00:54 +0000 (UTC), 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?

My question would be, what problem are you having that is causing you
to try to repair the connection?

"Kat Rabun" <> wrote in message news:hom71v$qp9$...
> 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

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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.

On Mon, 29 Mar 2010 07:49:18 +0000 (UTC), Kat Rabun
<> 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/...osts/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-s...-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_un..._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.

"Kat Rabun" <> wrote in message news:hopvtf$ur7$...
> On Mon, 29 Mar 2010 10:33:22 +0000 (UTC), Kat Rabun wrote:
>
>> So, I enabled the DNS Client service (as per recommendations here).
>>
>> However, I just realized I also use Comodo which has an option to use THEIR
>> DNS servers.
>>
>> Do you think this "feature" is partially the cause of what we're seeing?
>
> This is Comodo's description of the "Comodo Secure DNS Configuration"
> feature!
>
> Comodo Secure DNS - Another free service intended to provide you with
> a safer, smarter, and faster Internet:
> - Websites load faster because your domain name requests are resolved by
> our worldwide network of fully redundant DNS servers
> - Highly secure infrastructure reduces your exposure to DNS Cache Poisoning
> attacks
> - Parked, not in use, or commonly misspelled domains are automatically
> detected and forwarded
>
> If you use Comodo Secure DNS Servers:
> - Your computer's primary/secondary DNS settings will be changed to
> 156.154.70.22, 156.154.71.22
> If you are in a corporate network or using VPN connections, then contact
> your administrator before enabling this option to avoid potential
> connectivity issues.



Kat, read my responses to those links. In addition to Char's responses, which I agree with, you should really leave the service alone. I made some other recommendations.

And good question about your scenario. Is this a home machine, or a machine on a corp network?

Ace

On Mon, 29 Mar 2010 10:33:22 +0000 (UTC), Kat Rabun
<> wrote:

>On Mon, 29 Mar 2010 04:57:14 -0500, Char Jackson wrote:
>
>>>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.
>> In summary, I don't see any reason to disable it at all.
>
>I'm now thoroughly confused.
>
>I thought disabling DNS Caching or disabling the DNS Client service are,
>essentially, the same thing.
>
>These articles "seemed" to recommend disabling one or the other (which, I
>thought, was the same thing).

I hope someone will correct me if I'm wrong, but I assumed the DNS
Client service performed local DNS caching as one of its duties, so in
that respect they are related.

>I do understand your comments (and I don't disagree as I don't have enough
>information, e.g., who is John Navas, etc.); yet, I do make daily use of a
>very large hosts file (and for good reason).
>
>So, I enabled the DNS Client service (as per recommendations here).
>
>However, I just realized I also use Comodo which has an option to use THEIR
>DNS servers.
>
>Do you think this "feature" is partially the cause of what we're seeing?

No, I don't think it's related. You can use an application called
Namebench to test multiple DNS servers to see which are fastest for
you. http://code.google.com/p/namebench/

"Kat Rabun" <> wrote in message news:hoqv53$7cc$...
> On Mon, 29 Mar 2010 09:09:24 -0400, Ace Fekay [MVP-DS, MCT] wrote:
>
>> And good question about your scenario.
>
> It's just a home machine. WinXP Home. Not much of a network at all. I just
> realized Comodo has its own DNS servers, which I enabled, to see if that
> helps.


I'm not familiar with Comodo's DNS servers. You may want to try OpenDNS. I think that's a better solution than all of those entries in the hosts files slowing down your machine.

And leave the DNS Client service running.

Did you read my other response?

--
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.