How does Microsoft Exchange Server protocols work (Coexistence between 2013 + 2007)

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How does Microsoft Exchange Server protocols work (Coexistence between 2013 + 2007)

Whenever you deploy a newer version of Exchange Server in existing Exchange Organization it becomes the internet facing server and all incoming connections are proxy or redirected by the front server. In this article coexistence b/w exchange 2013 and 2007 is described. 

OWA – (Redirect) Should be pretty straight forward.  When a user whose mailbox still resides on 2007, accesses OWA via the 2013 CAS, they will be redirected back to 2007 via externalURL value: https://legacy.domain.com/owa

Set-OwaVirtualDirectory –Identity “ex2013\owa (Default Web Site)” –InternalUrlhttps://webmail.domain.com/owa –ExternalURL https://webmail.domain.com/owa

Set-OwaVirtualDirectory –Identity “ex2007\owa (Default Web Site)” –InternalUrlhttps://legacy.domain.com/owa –ExternalURL https://legacy.domain.com/owa

ActiveSync – (Proxy) I prefer to force ActiveSync to proxy from 2013 to 2007 as some ActiveSync devices don’t handle the redirect correctly.  In order to force a proxy scenario, the externalURL value for 2007 is set to $null.  The internalURL on 2007 should be configured with https://legacy.domain.com/Microsoft-Server-ActiveSync

Set-ActiveSyncVirtualDirectory –Identity “Ex2013\Microsoft-Server-ActiveSync (Default Web Site)” –InternalURL https://webmail.domain.com/Microsoft-Server-ActiveSync –ExternalURLhttps://webmail.domain.com/Microsoft-Server-ActiveSync

Set-ActiveSyncVirtualDirectory –Identity “Ex2007\Microsoft-Server-ActiveSync (Default Web Site)” –InternalURL https://legacy.domain.com/Microsoft-Server-ActiveSync –ExternalURL$null

Outlook Anywhere – (Proxy) All OA connections, both 2007 mailboxes and 2013 mailboxes will now connect via the 2013 CAS.  2013 will proxy connections back to 2007 for legacy mailboxes.  The externalHostName for both 2013 and 2007 should be the same, (webmail.domain.com).  Exchange 2007 does not support “Negotiate” authentication (See image below).  Therefore the externalClientAuthenticationMethods should be configured to match whatever is configured for 2007, either Basic or NTLM.  For OA to proxy from 2013 to 2007, the IISAuthenticationMethods on 2007 must be reconfigured to support both Basic and NTLM.  By default, Exchange 2007 IISAuthenticationMethods is set to just Basic.  NTLM must be added for the proxy to work.

Set-OutlookAnywhere –Identity “Ex2013\Rpc (Default Web Site)” –InternalHostname webmail.domain.com –ExternalHostName webmail.domain.com –ExternalClientAuthenticationMethod Basic –IISAuthenticationMethods Basic,NTLM

Set-OutlookAnywhere –Identity “Ex2007\Rpc (Default Web Site)”  –IISAuthenticationMethods Basic,NTLM

 

Exchange Web Services – (AutoDiscover) Autodiscover is used to retrieve the EWS configuration for the 2007 users.

Set-WebServicesVirtualDirectory –Identity “Ex2013\EWS (Default Web Site)” –InternalURLhttps://webmail.domain.com/EWS/Exchange.asmx –ExternalURLhttps://webmail.domain.com/EWS/Exchange.asmx

Set-WebServicesVirtualDirectory –Identity “Ex2007\EWS (Default Web Site)” –InternalURLhttps://legacy.domain.com/EWS/Exchange.asmx –ExternalURLhttps://legacy.domain.com/EWS/Exchange.asmx

 

AutoDiscover – Both the 2007 and 2013 SCP locator can be configured to point to the Autodiscover URL https://autodiscover.domain.com/Autodiscover/Autodiscover.xml.  DNS must be updated however so that the A record for Autodiscover.domain.com resolves to the 2013 CAS.

Set-ClientAccessServer –Identity Ex2013 –AutoDiscoverServiceInternalUrihttps://autodiscover.domain.com/Autodiscover/Autodiscover.xml

ECP –  Exchange 2007 did not have an ECP virtual directory.  Therefore, only the 2013 ECP virtual directory needs to be configured.

Set-EcpVirtualDirectory –Identity “Ex2013\ecp (Default Web Site)” –InternalURLhttps://webmail.domain.com/ecp –ExternalURL https://webmail.domain.com/ecp