9 Replies Latest reply: Jun 30, 2013 11:27 PM by Linc Davis
asjhabua Level 1 Level 1 (0 points)

Dear All,

we have corporate network , working with proxy gateway as MS ISA 2006 , And switches and wireless of CISCO,

we face regularly problem with slow internet browsing suddenly for all MAC pc / Air book.


If any one can guide me for this


Thank you



MacBook Pro
  • Linc Davis Level 10 Level 10 (168,930 points)

    From the menu bar, select

    System Preferences Network

    If the Network preference pane is locked, click the lock icon in the lower left corner and enter your password to unlock it. Then click the Advanced button and select the Hardware tab. Select

    Configure: Manually


    MTU: Custom

    Enter an MTU value of 1280.

    Click OK and then Apply. Test.

    You must apply the change before it takes effect.

    If the issue is resolved, experiment with higher MTU values until you find the highest one that works. The higher the MTU, the better the network interface will perform.

    If changing the MTU has no effect, restore the Configure setting to Automatically.

  • asjhabua Level 1 Level 1 (0 points)

    Dear Linc Davis,


    Thank you for your reply,

    but still after doing that i am facing the same problem,


    Thank you

  • Linc Davis Level 10 Level 10 (168,930 points)

    Can you connect to the Internet without going through the proxy? If so, do that and test. If you must use the proxy, the network administrator will have to solve the problem.

  • asjhabua Level 1 Level 1 (0 points)

    i am the network administrator


    it is not all time, suddenly once in a day all MAC PC / Notebook , getting slow browsing, i am not sure may be it is incomatibality or virus effect ?

    that is why i open the question here, as my other all windows PC working fine at same time, with fast internet browsing.



  • Linc Davis Level 10 Level 10 (168,930 points)

    It's not a virus. You haven't answered my question about bypassing the proxy.

  • asjhabua Level 1 Level 1 (0 points)

    yes, i can bypass the proxy by doing direct allow the IP from the Firewall, i have 1 MAC book pro. with same setting that directly allowed from firewall, and some of MAC PC that is working with Proxy setting, when this happen, almost all MAC PC / Laptop, that are with proxy or without proxy , start slow browsing, after few min. it back to normal.



    thank you

  • Linc Davis Level 10 Level 10 (168,930 points)

    What version of OS X is running on the Macs?

  • asjhabua Level 1 Level 1 (0 points)

    We are having

    Snow laperd , Mountaine lion, Lion , Mac Mini.

  • Linc Davis Level 10 Level 10 (168,930 points)

    Please read this whole message before doing anything.

    This procedure is a diagnostic test. It’s unlikely to solve your problem. Don’t be disappointed when you find that nothing has changed after you complete it.

    The purpose of the test is to determine whether the problem is caused by third-party software that loads automatically at startup or login, or by a peripheral device.


    Disconnect all wired peripherals except those needed for the test, and remove all aftermarket expansion cards. Boot in safe mode and log in to the account with the problem. Note: If FileVault is enabled, or if a firmware password is set, or if the boot volume is a software RAID, you can’t do this. Ask for further instructions.
    Safe mode is much slower to boot and run than normal, and some things won’t work at all, including sound output andWi-Fi on certain iMacs. The next normal boot may also be somewhat slow.

    The login screen appears even if you usually log in automatically. You must know your login password in order to log in. If you’ve forgotten the password, you will need to reset it before you begin.


    Test while in safe mode. Same problem?


    After testing, reboot as usual (i.e., not in safe mode) and verify that you still have the problem. Post the results of the test.