7 Replies Latest reply: Nov 21, 2013 5:47 PM by Linc Davis
JohnNY123 Level 1 (5 points)

I shut off DNS prefetching to test an internet performance problem that I'm having....

 

I then tried using the command:

 

defaults delete com.apple.safari WebKitDNSPrefetchingEnabled

 

....in a Terminal window to re-enable DNS prefetching and I got this message after hitting enter:

 

2013-11-18 20:21:24.479 defaults[359:507]

Domain (com.apple.safari) not found.

Defaults have not been changed.

 

Any idea what this means?  Am I to assume that because of this error that DNS prefetching has not been re-enabled correctly?

 

Thanks,

John

  • Linc Davis Level 10 (192,922 points)

    It means that prefetching wasn't disabled.

  • JohnNY123 Level 1 (5 points)

    Hi Linc....Thanks.  I'll take your word for it......and I say that  only because I had just issused the command to disable prefetching right before I typed in the re-enable command.  So.....it should have been disabled.

     

    Instead of using the command above to re-enable it, I tried this one instead that I read about somewhere:

     

    defaults write com.apple.safari WebKitDNSPrefetchingEnabled -boolean true

     

    .....and I got no error on that one.

     

    Is there a command that can be issued to tell whether pre-fetching is on or off?

  • Linc Davis Level 10 (192,922 points)
    defaults read -app Safari WebKitDNSPrefetchingEnabled
  • JohnNY123 Level 1 (5 points)

    This is what I got when I entered the 'defaults' command above:

     

    2013-11-19 18:48:11.458 defaults[971:507]

    The domain/default pair of (/Users/xxxxxxxxxxxxxxxx/Library/Preferences/com.apple.Safari, WebKitDNSPrefetchingEnabled) does not exist

     

    ....where the x's are my name.

     

    Sorry to bother you Linc.....but I'm not getting what this means.

  • Linc Davis Level 10 (192,922 points)

    The key isn't set. If you don't want prefetching disabled, you don't have to do anything.

  • JohnNY123 Level 1 (5 points)

    OK....I'm getting lost in these commands.....I apologize for being thick.

     

    Are these the correct commands for doing this?

     

    Disable pre-fetching use this command:

    defaults write com.apple.safari WebKitDNSPrefetchingEnabled -boolean false

     

    Enable pre-fetching use this command:

    defaults delete com.apple.safari WebKitDNSPrefetchingEnabled

  • Linc Davis Level 10 (192,922 points)

    Yes.