You may notice that with the Exchange 2013 defualt settings on Outlook Anywhere you are unable to open public folders located on you “old” Exchange 2010 server. You get an authentication pop up and the following error:
Microsoft has released a KB (http://support.microsoft.com/kb/2834139/en-us) article how to get that work.
Simply change your Outlook Anywhere settings to use internal and external NTLM with requirement of SSL:
Get-OutlookAnywhere –server ex01 | Set-OutlookAnywhere -ExternalClientAuthenticationMethod NTLM -InternalClientAuthenticationMethod NTLM -ExternalClientsRequireSsl $true -InternalClientsRequireSsl $true
The next time the client gets the Autodiscover File, it sets the Logon Network Security Settings of the Outlook Profile from “Anonymous Authentication” to “Negotiate Authentication” and you can open the public folders located on Exchange 2010.