* Can someone tell me how many certificates are needed for the setup below?
4 sites, 3 production sites and 1 DR site (1 DR site covers for all 3 production sites)
4 domains, 1 empty forest root and 3 child domains, 1 child domain for each of the 3 production sites.
9 Exchange 2010 multirole CAS/HT/MBX servers in 3 different child domains (3 Exchange servers in each of the 3 child domains)
 3-node DAGs (2 active mailbox servers in the production site, 1 passive mailbox server in DR. 1 DAG for each child domain)
4 CAS arrays, 1 in each site
Pair of F5 load balancers in each of the 4 sites
External mail hosted for a single mail domain
No Internet facing Exchange services like Outlook Anywhere, Outlook WebApp and ActiveSync
Outlook 2010 clients internally