Referenced from: https://technet.microsoft.com/en-us/library/aa998359%28v=exchg.150%29.aspx
- Start IIS Manager.
- Expand the local computer, expand Sites, and then click Default Web Site.
- At the bottom of the Default Web Site Home pane, click Features View if this option isn’t already selected.
- In the IIS section, double-click HTTP Redirect.
- Select the Redirect requests to this destination check box.
- Type the absolute path of the /owa virtual directory. For example, type https://mail.contoso.com/owa.
- Under Redirect Behavior, select the Only redirect requests to content in this directory (not subdirectories) check box.
- In the Status code list, click Found (302).
- In the Actions pane, click Apply.
- Click Default Web Site.
- In the Default Web Site Home pane, double-click SSL Settings.
- In SSL Settings, clear Require SSL.
- Open an Administrative Command Prompt window.
- Run the following commands:
cd %windir%\System32\Inetsrv
appcmd set config "Default Web Site/autodiscover" /section:httpredirect /enabled:false -commit:apphost
appcmd set config "Default Web Site/ecp" /section:httpredirect /enabled:false -commit:apphost
appcmd set config "Default Web Site/ews" /section:httpredirect /enabled:false -commit:apphost
appcmd set config "Default Web Site/owa" /section:httpredirect /enabled:false -commit:apphost
appcmd set config "Default Web Site/oab" /section:httpredirect /enabled:false -commit:apphost
appcmd set config "Default Web Site/powershell" /section:httpredirect /enabled:false -commit:apphost
appcmd set config "Default Web Site/rpc" /section:httpredirect /enabled:false -commit:apphost
appcmd set config "Default Web Site/rpcwithcert" /section:httpredirect /enabled:false -commit:apphost
appcmd set config "Default Web Site/Microsoft-Server-ActiveSync" /section:httpredirect /enabled:false -commit:apphost
Complete the changes by running iisreset
WARNING:
When you configure redirection from a top-level directory, a web.config file may be created under <drive>\Program Files\Microsoft\Exchange Server\<version>\ClientAccess\oab. If this has happened and you later remove redirection, Outlook may freeze when users click Send and Receive. To avoid this happening after you remove redirection, delete the web.config file from <drive>\Program Files\Microsoft\Exchange Server\<version>\ClientAccess\oab.