What is the best way to combine existing Hub and CAS servers? We currently have 4 exchange 2007 servers. They areMailbox, CAS, Hub and Edge servers on seperate dedicated machines. Now we want to conbime the CAS and Hub roles on the same machine. What is the best or recommended proceedure to combine them?

First of all, I assume that all servers (except Edge) are in same AD site.Why are you combining both server roles? I mean, you want to removeone serverand just keep three servers (1 mailbox, 1 cas+hub & 1 edge) or are you planning to implement 2 nodes for NLB CAS + Hub servers by combining them?Well, if you want only one server instead of 1 cas and 1 hub then you can simply install Hub transport server role in existing CAS server, change the internet mail send/receive connector accordingly and uninstall oldHub server.If you want to implement CAS + Hub NLB then below articles should help you.http://www.msexchange.org/articles_tutorials/exchange-server-2007/high-availability-recovery/load-balancing-exchange-2007-client-access-servers-windows-network-technology-part1.htmlhttp://www.msexchange.org/articles_tutorials/exchange-server-2007/planning-architecture/load-balancing-exchange-2007-sp1-hub-transport-servers-windows-network-load-balancing-technology-part1.htmlAmit Tank | MVP - Exchange | MCITP:EMA MCSA:M | http://ExchangeShare.WordPress.com

The Edge server is in a workgroup, the rest are in AD in the same site. We need to reduce the number of the physical machines. We wantto combine the roles of CAS & Hub on the same machine.

Depending on load on server you could combine MB, CAS and HUB on the same box.Edge is always on its on.lasse at humandata dot se, http://anewmessagehasarrived.blogspot.com

When combining the roles of Hub and CAS check your memory configuration. Best Practice is to have 1GB per CPU Core. You should have at least 8 GB of RAM on a Hub/CAS server16 being the optimal configuration. To merge the roles do a setup on your Exchagne 2007 CD and add the role or go to the command prompt and tyep setup /mode:install /roles:Hub or CAS dependning on what role you're adding.You should have at least 2 servers running the Hub and CAS roles for redundency. I would also load balance the CAS and HUB server roles if possible. With Exchange 2007 SP 1 it is possible to load balance the Hub Transport roles as well as the CAS servers (you could always load balance the CAS). If you needed to you could go to one server running the Mailbox, Hub, CAS roles and then one server running the Edge Transport role in the DMZ. You would lose redundency but it could work. Then you coudl considering LCR if you need to have some sort of recoverability. Don't forget the memory thought, you're going to want a lot of memory if you combine the three roles. BP