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Lots of DNS lookups while connecting to external Sharepoint Site RRS feed

  • Question

  • I have a scenario where a user is using IE 8 and trying to access an external Sharepoint Site and authenticating with NTLM. The login works fine, and resources download, but it takes over 3 minutes to load.

    I ran MS Visual Roundtrip Analyzer on the user's desktop and found that there are tens of extra DNS requests to the machines primary DNS provider. These extra DNS requests don't happen in Firefox, and the page loads absolutely fine.

    Not sure if this is a DNS cache issue, or if this is something related to NTLM authentication to the external Sharepoint site.  If the user connects to an external Sharepoint site that uses forms based authentication, there are no extra DNS lookups.

    Any help is greatly appreciated.


    Johnson Joseph
    • Edited by Mike Walsh FIN Friday, February 11, 2011 9:31 AM Getting not needed in Title. Tons won't be understood by many.
    • Moved by Mike Walsh FIN Friday, February 11, 2011 9:32 AM This has *nothing* at all to do with Accessibility. Look at all the other threads in that forum including the sticky thread (From:SharePoint - Accessibility (pre-SharePoint 2010))
    Thursday, February 10, 2011 9:38 PM

All replies

  • Hi,

    is there any proxy settings in IE 8 ?

    Please check and if its there for testing disable it and check.


    Regards, Pratik Vyas | SharePoint Consultant | http://sharepointpratik.blogspot.com/
    Friday, February 11, 2011 12:25 PM
  • There is definitely a proxy setting.  But unfortunately I will not be able to disable it.  Are there any known issues with accessing an external Sharepoint Site via NTLM authentication going through a proxy server? 

    Any KB articles on this?  


    Johnson Joseph
    Friday, February 11, 2011 2:44 PM
  • Hi,

    No this is not a known issue but as you have mentioned that it works fine with firefox , this is just to test with IE proxy.

    And as this issue is with external site , did you try to access the default zone site on IE ?


    Regards, Pratik Vyas | SharePoint Consultant | http://sharepointpratik.blogspot.com/
    Friday, February 11, 2011 2:54 PM
  • I believe the zone that is being used is the Internet zone.  Does this answer your question?


    Johnson Joseph
    Friday, February 11, 2011 3:02 PM
  • Hi,

    Yes the external site is in internet zone but what do you find if browse to Central admin > Operations > Alternate Access Mappings

    Do you have any default zone site for the internet zone site ?


    Regards, Pratik Vyas | SharePoint Consultant | http://sharepointpratik.blogspot.com/
    Friday, February 11, 2011 3:21 PM
  • Ok, the site is listed under the default zone.  The default zone authentication provider has configured: NTLM authentication with no anonymous access.


    Johnson Joseph
    Friday, February 11, 2011 8:07 PM