There are a number of services that my CAS servers will provide; OWA, Autodiscovery, Availability, and OAB. I know that I can use NLB with OWA to create a single namespace and perform some load balancing. However the autodiscovery service uses SCPs in AD and so doesn't require the use of NLB? I guess my question is, which CAS services should I configure to use my single NLB name space? I will have 3 CAS servers in the solution and all will be located in the same site. I want to provide some sort of automatic fault tolerance in the event of CAS server failure, and also provide a simple name space for my OWA clients.TIA!

Yes, SCPs are used for domain-joined clients and since Outlook will try all available SCPs until a connection is made, you don't generally need to modify the -InternalUrl parameter to point at an NLB name. However, if you've got non-domain joined clients or external users, etc, then these connect to the autodiscover service via either http://domain.com/autodiscover/autodiscover.xml or http://autodiscover.domain.com/autodiscover/autodiscover.xml so in this case you wouldmodify the -ExternalUrl parameter to point to one of the above URLs. For internal non-domain joined clients, you could usesplit DNS and point autodiscover to the NLB name, etc, etc.

Thanks Neil, so to summarise: All Outlook 2007 clients that are a member of the domain will use SCPs for Autodiscovery, Availability, and OAB All Outlook 2007 clients that are not a member of the domain or external can use the externalURL parameter to the NLB DNS name Only my internal OWA users actually require to use the NLB DNS nameThanks

Yes, that's basically it although my original post wasn't strictlyclear enough in that the -ExternalUrl parameter would be set for each server, i.e. Web services would be set to https://autodiscover.domain.com/ews/exchange.asmx, etc, but you get the idea. Of course, if you have ISA Server in the mix things can change a bit, i.e. ISA would likely be domain-joined and can also do load-balancing for HTTP protocols like OWA and EAS, etc.

Nice one Neil. Your help is much appreciated.