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Bypass Proxy for Local Addresses - Office 365 connection/ Outlook 2010 RRS feed

  • Question

  • This is a strange one.  Connectivity to Office 365 within our netwotk works fine although very slow for outlook 2010 client to initially connect. Once connected, it works ok.  I have done a netwotk trace using netmon to see if i can identify the reason for the slow startup (2 mins minumum for profile to load and for outlook to connect to exchange). The trace tell me that my local pc tries to make a direct connection to the office365 external IPs first, then tries the TMG proxy. Once it hits the proxy, it kicks into life and works.

    So it looks to me like it thinks the external IP address of office 365 is an internal address and spends it time trying all the ip addresses until it trys the proxy.  At this point, the Bypass Proxy Server for Local Addresses is ticked.

    As soon as i untick this box, all traffic heads directly to the proxy and of course it connects like lighting.  The exchange settings proxy is set in outlook for "on fast networks, connect using HTTP first, then connect using TCP/IP" (tick is on) and the same for slow networks.

    I cant for the life of me work out why it tries to connect directly to the external IPs first and not connect via TMG until i untick the Bypass Proxy Server for Local Addresses

    Would love any ideas that may assist.

    Wednesday, September 25, 2013 4:09 AM

Answers

  • Hi,

    What is the local intranet list? Is the office 365 is in the intranet list, if it is, please remove it then check the issue again. Maybe this issue is related with this list.

    In order to get a better solution, I also suggest you go to

    Office 365 Community

    http://community.office365.com/en-us/default.aspx

    for help. Check if they can provide you with some more valuable information about this issue.

    Regards,

    Yoladna

    Friday, September 27, 2013 2:25 AM
    Moderator

All replies

  • Hi,

    What is the local intranet list? Is the office 365 is in the intranet list, if it is, please remove it then check the issue again. Maybe this issue is related with this list.

    In order to get a better solution, I also suggest you go to

    Office 365 Community

    http://community.office365.com/en-us/default.aspx

    for help. Check if they can provide you with some more valuable information about this issue.

    Regards,

    Yoladna

    Friday, September 27, 2013 2:25 AM
    Moderator
  • Hi! I have exactly the same problem and no idea about how to resolve. Do you have any update TTPMan??
    Monday, October 7, 2013 8:38 AM
  • Same here. A customer get this behaviour on Outlook 2010SP2 and Outlook 2007SP3, both on the latest build. Any update from anyone?

    Best regards,

    Jesper Ståhle
    Office 365 MVP


    Jesper Ståhle MCT, MCITP:EA+EST, MCSA+M

    Thursday, October 10, 2013 7:48 AM
  • Hi,

    i have the same Problem with Outlook 2010 SP2 Bypass Proxyserver for internal Adresses ticked.

    When unticked Outlook Connection works fine.Autodiscover Entries in DNS are working and Connection Analyzer everything is OK.

    Somebody found out how to fix this Problem ?

    Regards,

    Andi

    Thursday, November 7, 2013 1:55 PM
  • We have been in discussions with Microsoft over the last few days on this issue - which is seen with Outlook 2007 versions onwards.  Extract from resolution communication from Microsoft:

    -------------------------------

    The issue you have raised is known as it has been reported and when you have a proxy set in Internet Explorer and “Bypass proxy settings for local addresses”, Outlook will attempt to connect to Office 365 directly – like the bypass rule would apply.

    Because the direct connection is blocked in the Firewall, Outlook needs to have the connections going in Timeout before attempting to connect using the Proxy.

    Your network trace proves the issue.

    Microsoft have scheduled a fix for Outlook 2010 in February 2014 cumulative update. A fix for Outlook 2013 will also follow, but Outlook 2007 will not be addressed because it is in Extended Support.

    There are two possible workarounds for this behaviour:

    First, and I wouldn’t recommend it, is to allow Direct traffic through the Firewall to Office 365.

    The advantage of this approach is that it will be done centralized and it will impact everyone immediately.
    Information about the O365 IP addresses

    There are two downsides to this behaviour:
    1.  First you need to maintain the Firewall exceptions as IP from O365 server can change without notice
    2.  Second, winhttp traffic may go through both proxy and direct and this can cause unforeseen behaviour.

    The second approach is to use a proxy pac instead of manually setting in the proxy and the exceptions.

    The advantage is that you will have centralized method to control how winhttp traffic goes and the issue will not be experienced anymore.

    If a single pac does not be fit, you can configure proxy pac files for each site requirements and use an IIS server to store it.

    Monday, December 23, 2013 4:04 PM
  • Microsoft have scheduled a fix for Outlook 2010 in February 2014 cumulative update. A fix for Outlook 2013 will also follow, but Outlook 2007 will not be addressed because it is in Extended Support.

    That is bullcrap that they wont fix Outlook 2007. I have 5000 seats of Exchange 2013 that I cannot deploy because of this issue.

    I also have an open Premier support case for a week and they have been of no help to date. If this is a known issue, it is mindnumbing that Office365 support (useless, they closed by case saying it was not their issue), and Premier support does not know about it... I opened my first ticket 12/17.

    Wednesday, January 8, 2014 12:45 AM
  • Its March now and I can't see any update from Microsoft that contains the fix that was mentioned in your post.  Do you have any further information as to whether there is a fix for this issue.

    Thanks.

    Thursday, March 20, 2014 2:41 AM
  • Same here still waiting on a fix.

    Surely this problem should be pretty high on the list for MS, as nobody with using a proxy with Outlook 2007,2010, or 2013 can use it. Which is pretty much any large company!!

    Tuesday, March 25, 2014 10:22 AM
  • Any word on hotfix? I can't find anything

    Thursday, May 15, 2014 12:53 AM
  • Same for us as well...we reported this issue over a year ago and keep being told it will be resolved...it's mid May and no resolution.  
    Thursday, May 22, 2014 2:32 AM
  • Hi, did you ever get a fix for this issue.
    Thursday, May 28, 2015 10:48 AM