Technet Multiple domain note

Our Current topology consist of:

• 1 Forest – root.corp (Windows 2003 Functional Level) – with no users or any objects.
• 3 Child Domains – AA.root.corp / bb.root.corp / cc.root.corp
• Each child domain has it’s own Exchange 2007 server, and the external email address for all users are the same @root.com
• The global settings are kept in the configuration container.
• Each Child domain was installed with an OCS 2007 standard edition, and is working properly internally between users.
• Internal CA server is existing on the root domain for certificates.
• Port 5061 & 5062 is opened between the servers.
• All services are running, and the installations were completed successfully on each server including the certificates enrollment.
• Each OCS server have the Root CA certificate installed.
• the SIP domains are: root.corp, aa.root.corp, bb.root.corp & cc.root.corp
• Each certificate was issued with the subject alternate name of it’s FQDN name.
  for example on the server :AA-OCS.aa.root.corp those are the SAN:
  DNS Name=aa-ocs.aa.root.corp

  DNS Name=sip.root.corp

  DNS Name=sip.aa.root.corp

• in the DNS, there is a SRV record of  _sipinternaltls.<domain name> that points to AA-OCS.aa.root.corp for all other child domain (bb.root.corp and cc.root.corp).