i have CAS2010-CAS2007 infrastrcuture, i need to configure the coexistence scenario for OWA users, i'm in testing phase now, is it must to install certificate ?? since i'm testing & can't purchase a certificate, will redirection work fine without ssl ceritifcate ?

Hi, You can work without SSL certificate and everything will works just fine beside you'll receive notification on your web browser that the site isn't secure with valid certificate, you can ignore that. In production it's recommended to purchase and associate to the CAS a valid certificate from known SAN Certificate generator.Netanel Ben-Shushan, MCSA/E, MCTS, MCITP. IT Consultant & Trainer | Website (Hebrew): http://www.ben-shushan.net | IT Services: http://www.ben-shushan.net/services | Weblog (Hebrew): http://blogs.microsoft.co.il/blogs/netanelb | E-mail: msilforums@ben-shushan.net

I agree, but use HTTPS and not HTTP, if you're using HTTP the information is sent in cleartext It's a pretty small cost to purchase a certificate from godaddy. digicert etcJonas Andersson MCTS: Microsoft Exchange Server 2007/2010 | MCITP: EMA 2007/2010 | MCSE/MCSA Blog: http://www.testlabs.se/blog

Read the following article : http://technet.microsoft.com/en-us/library/bb310763.aspx But you will need SAN certificate for Exchange 2010 Server.