We're running two AD sites with Exchange 2010 SP3. One site is Internet facing and the other is not. OWA and Activesync work for mailboxes on the Exchange servers that are Internet facing. OWA and Activesync are not working for mailboxes in the non-Internet facing site. The two AD sites have two different CAS Array names.
The CAS servers in the Internet facing site are actually multi-role servers (Mailbox, Hub Transport, and CAS). The CAS servers in the Internet facing site also use an F5 load balancer.
The CAS servers in the non-Internet facing site are CAS\HT servers only. They are in an NLB cluster because we could not afford an F5 load balancer in the non-Internet facing site.
The external and internal URLs are populated on the Internet facing servers but the external URL is not populated on the non-Internet facing servers. The non-Internet facing servers have the internal URL populated with the hostname of the CAS Array in the non-Internet facing site.
When I use the external URL for OWA and Activesync to access a mailbox in the non-Internet facing site it does not work. However when I use the hostname for the CAS Array in the non-Internet facing site OWA and Activesync work. Any help ore suggestions would be greatly appreciated.