Hi Experts!

I have a quick question around outlook behaviour.

How does outlook choose whether to use the external / internal outlook anywhere access url? Same for OAB/ EWS Urls.

Thanks, Amine

Hi Amine,

Thank you for your question.

As Ed said, when outlook client is  domain-joined and connected to Active Directory, it will pick up Autodiscover from an SCP record, in which case it will use the internal URLs. 

When the outlook client is on Internet, outlook will attempt to connect to AD to retrieve SCP object but fail because the computer is not on domain, outlook prompts for email address and password. Outlook will attempt to locate Autodiscover using the known urls:Autodiscover.domain.com or autodiscover.domain.com/autodiscoverw(which we has registered in ISP). Outlook will connector to autodiscover URL and contain setting. Using Exchange Http, outlook can connector mailbox server and availability using External URL which we specific.

We could refer to the following link to learn SCP:

https://msdn.microsoft.com/en-us/library/office/jj900169%28v=exchg.150%29.aspx

If there are any questions regarding this issue, please be free to let me know. 

Best Regard,

Jim

Thanks a lot for your answers. That's really helpful.

to confirm : a workgroup machine will always pick the the external URL regardless of whether it is internal or external.

Also trying to make the analogy with ActiveSync Client is a bit confusing:

ActiveSync will always use the DNS to perform autodiscover so how will it know whether it is internal or external.

Thanks again!

Thanks a lot for your answers. That's really helpful.

to confirm : a workgroup machine will always pick the the external URL regardless of whether it is internal or external.

Also trying to make the analogy with ActiveSync Client is a bit confusing:

ActiveSync will always use the DNS to perform autodiscover so how will it know whether it is internal or external.

Thanks again!

Hi Amine,

to confirm : a workgroup machine will always pick the the external URL regardless of whether it is internal or external.

A: If the outlook is on a workgroup machine, we will manually configure profile and didnt use autodiscover. So workgroup machine didnt use internal URL or external URL. 

In fact, Active Sync client is same as workgroup machine, and it will use DNS instead of internal URL or external URL.

If there are any questions regarding this issue, please be free to let me know. 

Best Regard,

Are you sure about that Jim?  My understanding is that Outlook on a workgroup machine will use DNS Autodiscover records (company.com, autodiscover.company.com or an SRV record in th