Hello,
We have a new Exchange 2013 environment having some issues with OutlookAnywhere published through UAG. When we try to configure a client externally via autodiscover the fiddler trace shows that it hits the autodiscover URL fine and returns the needed mailbox info. Once it hits the /rpc/rpcproxy.dll URL it fails with 401 unauthorized. The trace also seems to be stating that it is attempting to use NTLM and not Basic as specified in the config
Get-OutlookAnywhereExternalHostname : webmail.domain.com
InternalHostname : webmail.domain.com
ExternalClientAuthenticationMethod : Basic
InternalClientAuthenticationMethod : Ntlm
IISAuthenticationMethods : {Basic, Ntlm, Negotiate}
ExternalClientsRequireSsl : True
The behavior we see is a repeated prompt for credentials that almost seems to be a loop. What it also seems is that because the internal and external URL used are the same it is using the authentication method for Internal as opposed to what is specified for External. I will also note that internally OutlookAnywhere and Autodiscover are working fine.