Disabling DNS Prefetching

Question

Disabling DNS Prefetching

All,

anyone know how to disable DNS prefetching in safari 5?

I want to do some testing of page load times with it on and off as I have severe hang times loading random url's post safari 5 upgrade.

Thx,
Michael

MBP, Mac OS X (10.6.4)

Posted on Jul 25, 2010 7:03 PM

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Answer 1

Jul 26, 2010 1:26 AM in response to Michael Missing

HI,

I found instructions for Firefox but not Safari.

http://www.ehow.com/how4700632disable-prefetching-firefox-improve-performance.html

Since you are experiencing lags, try troubleshooting.

From the Safari Menu Bar, click Safari / Reset Safari. Select the top 5 buttons and click Reset.

Go here for trouble shooting 3rd party plugins or input managers which might be causing the problem. Safari: Add-ons may cause Safari to unexpectedly quit or have performance issues

Go to the Safari Menu Bar, click Safari/Preferences. Make note of all the preferences under each tab. Quit Safari. Now go to ~/Library/Preferences and move this file com.apple.safari.plist to the Desktop.

Relaunch Safari and see if that makes a difference. If not, move the .plist file back to the Preferences folder. If Safari functions as it should, move that .plist file to the Trash.

Carolyn 🙂

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Answer 2

Jul 26, 2010 7:35 PM in response to Carolyn Samit

Hi Carolyn,

Thanks for the feedback but I've been through the t-shooting churn already - nothing seems to work. This only started happening once I upgraded to Safari 5.

ps... yes I've done just about every documented t-shooting trick just short of sacrificing chickens 🙂

Cheers,
Michael

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Answer 3

andyBall_uk

Level 7

20,516 points

Jul 27, 2010 12:54 AM in response to Michael Missing

Hi Michael

check your router/modem logs, you may find perceived dos/flood attacks going to the dns servers - I do.

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Answer 4

Jul 29, 2010 7:44 PM in response to andyBall_uk

Hi Andy,

The problem I have may have been fixed with the latest Safari 5.0.1 patch. They fixed a recently discovered issue with dns-prefetching with may "overburden" some routers. I'm not sure if this ties to the page load time issue I had once I upgraded to 5.0 but post-patch I have not seen any unbearable delays with page loads to the sites where I experienced them.

Cheers,
Michael

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Answer 5

TildeBee

Level 7

31,917 points

Jul 29, 2010 7:51 PM in response to Michael Missing

That's great news, Michael.
The prefetching situation was addressed with the upgrade.
Good that it appears to have worked in your case.

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Answer 6

RonL

Level 1

52 points

Sep 15, 2010 5:26 PM in response to TildeBee

+"The prefetching situation was addressed with the upgrade."+ (Safari 5.0.1)

The update did not completely solve the loading issue for me (though the previous advice to change my DNS settings definitely helped considerably)... but the advice I read today about how to *disable DNS Prefetching* via the Terminal seems to have solved it.

* http://support.apple.com/kb/TS3408*

It may take a while to see if it has been completely solved.

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Answer 7

RonL

Level 1

52 points

Sep 15, 2010 5:51 PM in response to RonL

DNS prefetching appears to send more requests than allowed by some ISPs...

* http://appletoolbox.com/2010/09/fix-safari-slowness-stalled-page-loads-by-disabl ing-dns-prefetching/*

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Answer 8

Sep 17, 2010 8:02 PM in response to Michael Missing

Open up terminal
Type or copy this line:

defaults write com.apple.safari WebKitDNSPrefetchingEnabled -boolean false

Restart Safari

DNS prefetch is total crap for me, massive slowdown & changing to other DNS servers didn't help.

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Answer 9

RonL

Level 1

52 points

Sep 17, 2010 8:28 PM in response to The Lone Deranger

*Macworld article:*

Bugs & Fixes: DNS prefetching can cause Safari problems

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Answer 10

Oct 5, 2010 3:55 PM in response to RonL

Seems to be a temp fix as it come right back. Hmmmmm

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Answer 11

Klaus1

Level 9

52,749 points

Oct 5, 2010 4:18 PM in response to michaelmckeever9

This is described here:

http://support.apple.com/kb/TS3408?viewlocale=en_US

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Answer 12

Oct 5, 2010 4:51 PM in response to Klaus1

I typed in this command and hit enter, it come right back and this time it didn't work.

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Answer 13

andyBall_uk

Level 7

20,516 points

Oct 5, 2010 5:53 PM in response to michaelmckeever9

it come right back and this time it didn't work.

the setting altered or deleted itself ?
it will go away if the safari plist is removed, but otherwise should stick around until removed or altered via Terminal again.

what is it set to now?

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Answer 14

Oct 5, 2010 8:01 PM in response to andyBall_uk

As far as I can tell it's still on, but I have had to run the command several time ad it does not hold at all. Just now some images didn't load and I got a can't connect to the server massage.

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Answer 15

andyBall_uk

Level 7

20,516 points

Oct 6, 2010 5:06 AM in response to michaelmckeever9

michaelmckeever9 wrote:
As far as I can tell it's still on, but I have had to run the command several time ad it does not hold at all. Just now some images didn't load and I got a can't connect to the server massage.

I see - sounds as if there's something else amiss.

defaults read com.apple.safari WebKitDNSPrefetchingEnabled

will confirm the setting - it is set per user & (probably) needs Safari restarted to take effect.

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