Outlook Anywhere in Outlook 2016 with Exchange 2010

Outlook Anywhere in Outlook 2016 with Exchange 2010

With a default Exchange 2010 Outlook Anywhere configuration it takes around 30 seconds after Outlook 2016 startup before the client manages to connects to the Exchange server. The reason is that the Exchange 2010 Autodiscover service tells the client to try a regular RPC/TCP connection before resorting to a RPC/HTTP connection. This was easy to change in previous versions of Outlook but not in Outlook 2016.
I’ve seen plenty of people complaining about it on the Technet forums and elsewhere but I haven’t seen anyone getting a solution but I’ve found a few ways to solve the problem.

Outlook 2013 connection settings

Let’s look at how this was handled in Outlook 2013.
The easiest way was to go into account options and modify the connection settings by checking the On fast networks, connect using HTTP first, then connect using TCP/IP option.


Fast networks are all network interfaces with a link speed higher than 128Kbps which pretty much means all network interfaces unless you’re toying around with some obsolete dialup adapter.

Outlook 2016 connection settings

Now let’s look at the Outlook 2016 Connection settings.

That’s right. There are no Connection settings in Outlook 2016 and that’s because Outlook doesn’t expose any ways of configuring an Exchange server connection other than Autodiscover.

It is possible to set Exchange Server 2010 to prefer HTTP before TCP/IP (or rather RPC/HTTP before RPC/TCP) but that means that all clients will pick up that setting and all clients will connect to your CAS using HTTP, even clients on internal networks.
This is done using the Set-OutlookProvider Cmdlet in Exchange Management Shell:

Set-OutlookProvider EXPR -OutlookProviderFlags:ServerExclusiveConnect

The Set-OutlookProvider Cmdlet is documented at https://technet.microsoft.com/en-us/library/bb123683(v=exchg.141).aspx

As stated in the above documentation, running all connections over HTTP is not recommended for Exchange 2010 unless most clients use Outlook Anywhere as their primary connection method (it is recommended for Exchange 2013 and Exchange 2016 though).

“The OutlookProviderFlags parameter specifies that Outlook 2010 clients should connect using RPC over HTTP (Outlook Anywhere) before trying RPC over TCP connections. This increases the speed at which Outlook 2010 clients will connect when clients are primarily accessing Exchange over the Internet. The value can be set to ServerExclusiveConnect or to None to clear the flags. For Outlook 2010 clients that access Exchange over both organization intranets and the Internet, the recommended value is None, which is also the default setting.”

Configuring connection settings using group policy

It turns out that you can also configure the connection settings using Group Policy the same way as in earlier versions of Outlook.
This could be a better way if your clients mainly connect to Exchange from Internal networks but you still want to configure some clients for quick Outlook Anywhere access.

The GPO settings are found here:
User Configuration\Administrative Templates\Microsoft Outlook 2016\Account Settings\Exchange


The GPO settings that control the options previously found on the Connection tab are:

  • RPC/HTTP Connection Flags
  • RPC Proxy Authentication Setting
  • RPC Proxy Server Name
  • Only connect if Proxy Server certificate has this principal name

The Exchange 2010 Autodiscover functionality provides most values needed and the only thing you should need to change is to enable flag 4 of the RPC/HTTP Connection Flags.
The flags in the RPC/HTTP Connection Flags are:

  • 1: Enables the ‘Connect to Microsoft Exchange using HTTP checkbox’ on the Connection tab.
  • 2: Enables the ‘Connect using SSL only’ checkbox
  • 3: Enables the ‘Only connect to proxy servers that have this principal name in their certificate’ checkbox
  • 4: Enables the ‘On fast networks, connect using HTTP first, then connect using TCP/IP’ checkbox
  • 5: Enables the ‘On slow networks, connect using HTTP first, then connect using TCP/IP’ checkbox

I have used Flags 1+2+3+4+5 which enables all checkboxes the way it used to look in Outlook 2013 for me.

If you don’t have a way to target only your Outlook Anywhere users or you don’t want to use a GPO for some reason you can use the registry to apply these policy settings too.

They registry key where the below values should be stored is:


The registry path normally doesn’t exist and has to be created.

Values and meanings

  • ProxyServerFlags (DWORD)
    Corresponds to the “RPC/HTTP Connection Flags” policy
    Can have one of the following decimal values:

    • 0 (Not configured = Autodiscover)
    • 33 (Flags 1+5)
    • 35 (Flags 1+2+5)
    • 39 (Flags 1+2+3+5)
    • 41 (Flags 1+4+5)
    • 43 (Flags 1+2+4+5)
    • 47 (Flags 1+2+3+4+5)
  • ProxyAuthenticationService (DWORD)
    Corresponds to the “RPC Proxy Authentication Setting” policy
    Can have one of the following decimal values:

    • 1 (Basic Authentication)
    • 2 (NTLM)
    • 3 (Negotiate)
    • 4 (Certificate)
  • ProxyServerName (Expandable String Value)
    Corresponds to the “RPC Proxy Server Name” policy
    Your Outlook Anywhere host name. I.e. mail.fourthcoffee.com
  • ProxyServerPrincipalName (Expandable String Value)
    Corresponds to the “Only connect if Proxy Server certificate has this principal name” policy
    Your Outlook Anywhere principle name prefixed by msstd:
    I.e. msstd:mail.fourthcoffee.com


15 thoughts on “Outlook Anywhere in Outlook 2016 with Exchange 2010

  1. Hi, We are using Exchange 2010 SP3 in our organization.Our Outlook 2016 successfully connect outside the network (Outlook Anywhere) but when we try to configure within network (LAN) it prompt credentials on ” Searching for test@xyz.com settings”.We put domain/user id and password but it not accept. Please help to resolve this issue.Its Urgent.

    1. Hello Irshad

      I have same problem. Have you found solution in your organization?

  2. I just followed this using the GPO. I have outlook connecting to Office 365 and also a 2010 server. 2010 server always gave me a delay when out of the office (I am usually out of the office). After hitting enabled, it connects upon opening outlook. Questions, I have left the default of Flags 1+2+3+4+5. is this ok? Should I see a connection tab under the account settings after this is set? I do not see it and wonder if I should

    1. You will not see the connection tab no matter how you configure these settings. It’s gone.
      The flags 1-5 represent the checkboxes on the tabs that you don’t see. Which flag that corresponds to which checkbox is explained text and pictures in this article. Option 1 is on the Connection tab and option 2-5 is in the Microsoft Exchange Proxy Settings dialog.
      The default 1+2+3+4+5 is probably ok unless you used to select different options in earlier versions of Outlook.

  3. I did all the registry settings and there was some improvement, but I found that it was just a workaround of the real issue which was a public DNS entry that had been in place for years.
    If the internal name of the Exchange server (the name that autodiscover provides to Outlook as the internal hostname) is resolvable to an IP address from outside your network, then Outlook Anywhere will try to connect to this hostname/IP via TCP/IP and this will cause the delay. The “connect using HTTP first, then connect using TCP/IP” settings will mitigate this, but according to the author of the Experts Exchange answer, the problem is not with Outlook or the client side, but that the Exchange environment is not set up correctly. Make sure that the internal name of Exchange server is NOT resovable and the problem will be solved for all clients without the need for client modications. The article also mentions that the resolution is more involved if the internal and the external FQDN are the same, i.e. internal name and OWA URL are both mail.domain.com.

  4. If I want to use the registry edit method, when do I create the new key(s) and input the values I want? Before I install Office 2016, after I install Office 2016 but before I open Outlook for the first time? Also, do the registry settings apply to all profiles, and all email accounts within each profile? If so, is there a way to make the Connection settings only apply to one profile, or even one email account within a profile? Clear on the registry entries, confused on implementation and timing.

    1. Since the registry keys are created under HKEY_CURRENT_USER they only affect the current user.
      You can make the edit any time you like. You only need to restart Outlook afterwards.

  5. Xerxes, did this work for you. I just did a complete reset to win10 pro and reinstalled office 365. the latest version of outlook 2016.
    I created the key HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\16.0\Outlook\RPC and added only the one ProxyServerFlags (DWORD) and set it to 41 decimal
    Outlook would not get past the loading profile display. DO I need to add all the DWORDS for this to work

  6. Thank You! We recently started rolling out Outlook 2016 at a client site who has Exchange 2010, working perfectly with previous Outlook versions. Autodiscover works and profile gets created using 2016, but then got generic error opening ‘Cannot open set of folders, you must connect to exchange blah blah’. After hours of troubleshooting, installing service packs and rollups, setting these values has resolved the issue.

    Many many many thanks for your post!!

    1. Simon, I have the same issue and requirement. What settings ultimately did the trick?

  7. Thanks, for the blog post it really helped, but:
    As far as I see on the behavior, the registry change numbers are in hexadecimal format and not decimal!

    In the decimal the correct data is 71.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s