Hello Guys.

I really hope someone can help me resolve this asap. I have spent hours upon hours pouring through blogs and forums and applied and double checked every conceivable autodiscover tool and can not resolve this.

Scenario: Server 2012 Standard with Exchange 2013. Split-Brain DNS, (Internal = domain.local) (External = mail.domain.com.na)

I have applied CNAME, PTR, SRV and Autodiscover.xml, but still Exchange Connectivity (Autodiscover) keeps failing on all points.

Everything else is working 100%, OWA, Activesync, IMAP etc.

But I have 1 client PC with Windows 8 Single Language that can obviously not join the domain, and the client doesn't want to use IMAP saying it looks different?? Don't know why. But he wants to use Exchange.

From outlook 2013 I configure it as follows:

Server: server.domain.local

Username: domain user account

Exchange Proxy Server: mail.domain.com

Connection: SSL, HTTP and HTTPS, authentication "auto negotiate"

It just comes back with "Unable to resolve username"

Is it necessary to, as with "mail.domain.com" point "autodiscover.domain.com" to the public IP?

Thank you in advance.

Kind Regards

Hentie Loots

• Edited by EagleClaw1976 17 hours 2 minutes ago

If a computer is domain-joined, Outlook gets its Autodiscover from the SCP record that's in AD.  If the computer is not domain-joined, it will look to DNS to find autodiscover.maildomain.com, where maildomain.com is the e-mail domain that the user enters for the e-mail address, and then Autodiscover will return the URLs specified in the various Set- cmdlets (Set-OutlookAnywhere, Set-WebServicesVirtualDirectory, Set-OabVirtualDirectory, etc.).  These all must be in the DNS to which the client is looking.  If the client PC is configured to use internal DNS, that's all that's required.  If you want devices to work from outside the network, then these DNS entries must be in Internet DNS.

An alternative to publishing the DNS records to the Internet is that you can require users to establish a VPN connection 

Hello Ed and thank you for the reply.

This is exactly where I get a bit hazy.

Some of the forums I have read talk about "internal" and "external" DNS Zones.

Internal is fine. But what do you mean by "External / Internet" DNS? Is it something my ISP has to setup on the internet dns? Like with the MX Records that point mail.domain.com to the public IP? Or is it a new zone I need to create on the Server's DNS? Reverse Lookup Zone or something?

I can't find anything on the web about "External DNS Zone". I completely lost with where exactly on this split-brain dns between .local and .com and Foreward and Reverse Lookup Zone I need to create the PTR, SRV, CNAME and A records.

Like I said, everything else works like a well oiled machine. It is only the Autodiscovery from the internet that keeps failing, so Outlook keeps saying exchange is offline and it wasn't able to resolve the username.

I get the same issue even when connected via VPN.

"The action cannot be completed. The connection to Microsoft Exchange is unavailable. Outlook must be online or connected to complete this action."

Hoping to hear back soon.

Thanks again.

Hentie Loots

• Edited by EagleClaw1976 12 hours 13 minutes ago

It's set up by your ISP, your Internet-facing DNS serer, or a DNS provider.  Your MX records would be in your external DNS zone.  Internal DNS servers are the ones clients on your internal network look to, and external DNS is what is published to the Internet.  Internal DNS usually has your internal non-routable IP addresses (though it may have external addresses in some cases) but external DNS must have Internet IP addresses.

For external clients, i.e., computers that cannot reach the AD SCP records because they're either not domain-joined or they're outside your network, Autodiscover returns the external URLs.

Hi Hentie,

If you have setup all correctly and currently connected to your internal network using Win8 non domain PC.

Try opening this on internet explorer of the PC. You should be able to get through some XML data.

<Message>Invalid Request</Message>

https://autodiscover.domain.com/Autodiscover/Autodiscover.xml