Hi We are running Exchange 2010. In Europe we have one DAG across two AD sites (London/Paris). We have the same set up in America (LA/ San-Fransisco). One of our users whose mailbox is located in London is going to be travelling to LA for the week. So they'll be giving him a PC in LA with Outlook installed. Questions - i. When he opens Outlook on the LA PC, which CAS array will he connect to? Directly to the one in London, or to the one in LA which will then proxy the connection to the one in London? ii. If he opens his Outlook on the LA PC and then adds a secondary mailbox that is located on an Exchange 2010 LA server, how will the connectivity be?

Outlook will connect to the LDN CAS Array. Proxying occurs for OWA.The same as if the user opened a secondary mailbox in London. It will connect locally.Sukh

Outlook will connect to the LDN CAS Array. Proxying occurs for OWA.The same as if the user opened a secondary mailbox in London. It will connect locally. Sukh Disagree with the second one. The connection point is based on rpcclientaccessserver value. So, the connection point will be the casarray that is located in the same AD site as the mailbox database. But for Autodiscover service connection, it will connect to the AD site where user is logged on. Fiona Liao TechNet Community Support

@Fiona - Not sure what you disagree on here? Are you saying that it will connect to the LA CAS?Sukh

Hi Sukh, If user's mailbox is located in London/Paris, then Outlook will connect to CAS array in London/Paris.Fiona Liao TechNet Community Support

Hi Fiona Think you misunderstood my point 2. That;s what it reads.Sukh

sorry about that. And thanks for your clarification.Fiona Liao TechNet Community Support

Sorry Sukh, I'm not sure what you mean by this; "The same as if the user opened a secondary mailbox in London. It will connect locally." Could you clarify that?

What I mean is that it will connect to the local CAS server whereever the mailbox is located. That LDN example was just an example.Sukh

Hi We are running Exchange 2010. In Europe we have one DAG across two AD sites (London/Paris). We have the same set up in America (LA/ San-Fransisco). One of our users whose mailbox is located in London is going to be travelling to LA for the week. So they'll be giving him a PC in LA with Outlook installed. Questions - i. When he opens Outlook on the LA PC, which CAS array will he connect to? Directly to the one in London, or to the one in LA which will then proxy the connection to the one in London? ii. If he opens his Outlook on the LA PC and then adds a secondary mailbox that is located on an Exchange 2010 LA server, how will the connectivity be? That depends. What protocol? Outlook Anywhere or MAPI?