One of my clients fell foul of that BT building flooding last week and it took 48 hours to get the wired broadband back again. I vowed to investigate a suitable fall back solution for this and other sites. The system is fairly classic SBS2003 with ISA2004 and Exchange 2003 operating SMTP mail only (no POP) Will need SBS2008/Exchange2007 info too.
Without going through the whole considered solution can anyone tell me if its possible to get static IPs allocated to wireless broadband devices. I don't think its posible to setup mail enabled systems using DDNS due to various antispaming technologies these days.
I'm thinking along the lines of two mx records with different distance settings so when the primary fails it falls back to the secondary. Even if the mx record can reference a DDNS record somehow I don't know if email land tolerates a server potentially changing IP address like that.
Any pointers to back ground on this would be helpfull