>Could you elaborate a bit more on the DDNS solution?
It's the usual DNS-as-load-balancer but without proprietary hardware and is "postfix-aware" since it is postfix + Unix params, "agents", that are informing the dynamic updating of the ip addresses. Load balancers that try to judge a web server's or smtp server's load by hitting port 80 and 25 from the outside only are not incisive. With an "intelligent agent" inside the IMGate box sounding out and reporting the box's loads, the load balancing is much more precise. It's load balancing and fail over (in the sense that a service's disappearance is "infinite load") Len
