Outlook connects with RPC over HTTP while inside network
So I have run across an interesting situation. I have an Exchange 2007 environment with Outlook 2007/2010 clients. I have client systems on 3 vlans. On one of those vlans Outlook clients connect normally with RPC with no issues. On the other two vlans however Outlook switches to RPC over HTTP and prompts users to login. The problem is that they don't want the login prompt coming up for users who are internal. If they disable RPC over HTTP in Outlook then it will connect fine with no issues. But when autodiscover refreshes it kicks back to RPC over HTTP and starts prompting for a login again. My first instinct was to get a third party cert since I think having the self signed cert is why it prompts users to login so often. However they want to know why Outlook keeps using RPC over HTTP instead of regular RPC to communicate with Exchange. It's still using the defaut settings, fast=lan and slow=rpc over http.Vincent Sprague
September 7th, 2012 10:26am

Uncheck on slow networks....also when the user is prompted for password, click the box to save password. The uncheck on slow networks tends to switch to outlook anywhere for my users when they dock\undock laptops sometimes.James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com
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September 7th, 2012 11:30am

They are using desktops, not laptops. The problem with unchecking slow networks is that when the autodiscover refresh happens it just checks it again.Vincent Sprague
September 7th, 2012 11:31am

For 2010 you can disable that specific setting during the autodiscover push, however you can't for 2007, the only option is to disable the entire outlook anwhere config which is not good because than you would have to configure new clients outlook anywhere settings manually. At this point you need to look into why outlook is detecting a slow connection. If you ctrl + right click the outlook icon on right bottom tray and do connection status check the response times against a client on the good vlan and see if there is a bigger delay.James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com
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September 7th, 2012 11:41am

Hello, I would like to inform this should be a hard coded behavior. Once Outlook Anywhere feature is configured on a client access server, an EXPR entry is created. Then the autodiscover application (Outlook) picks up the change and publish it, along with the urls for OAB, EWS & Availability. This basically force the automatic propagation of settings into the profile, including the checkbox for Connect to Microsoft Exchange using HTTP and filling the information for the HTTP proxy and authentication methods. Generally, We could disable this option on the internal Outlook client by Group Policy, please download the GPO file from the following link of KB 961112. http://download.microsoft.com/download/F/B/C/FBC43645-89EA-4FB4-828C-DFE27C360233/article-961112.adm After adding the GPO template (article-961112.adm) to the group policy object editor: -Browse to Article 961112 Policy Settings | Outlook Anywhere (RPC/HTTP) -Open the RPC/HTTP Connection flags. -Choose Enabled, select No flags from the drop-down box, Apply and Ok your way out from the GPO. -Test Microsoft Outlook; "Connect to Microsoft Exchange using HTTP" should now be disabled/Grayed out, and the checkbox should be unchecked. Thanks, Simon
September 10th, 2012 4:38am

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