Have a small exchange cluster that recently had mail start queuing after a smarthost we were using went down for a little while. Client was not happy, they want redundancy. I have already put in monitoring to watch the queue length but am looking at adding multiple exit points for mail.
I know that I can add additional smarthosts to the current connector, so adding a second smarthost provider may be an option.
I was wondering, if I had the current smarthost connector, address space *, weight 1 and added a second connector, address space * weight 2 would messages that cannot flow over the first connector try the second? I can configure the second connector that goes out to the internet and setup ptr and spf records so if the smarthost fails we go to more traditional means.