I've noticed that I can't the the notification SMTP server to anything other than a static host (it won't allow me to create one "on the fly" or even Drag n' Drop a predefined one) ... This is kind of an annoyance... as ISPs do change IPs for their SMTP services from time to time, as they upgrade systems, etc. IMHO, we should be allowed to set this using a DNS (or multiple DNS) host.
Indeed, many ISPs use more than one IP address for SMTP mail relay... take Bellsouth.net for example; mail.bellsouth.net resolves to 2 different IP addresses (for failover and load balancing, no doubt)...