Microsoft released the HMC 4.0 which focuses on the performance maximums of Exchange 2007 in a hosted environment, but some of the results can be applied to large Exchange 2007 deployments.

Some highlights from the report include:

• · So the guidance is somewhere between 3,750 and 6,000 Outlook Anywhere clients per CAS depending on the specific deployment.

• If all client connections to CAS appear to come from the internal VIP (behind an ISA or proxy) then it max out at 60,000 client connections because every client connection has the same source IP, source port, destination IP, and destination port mapping.

• RPC Proxy only uses the first IP in the binding order and ignores any additional IPs

• It was determined that the maximum number of SMTP messages a single Hub Transport server (single CPU dual core with 2 GB RAM) can sustain was 69 messages per second.