Fail-over

[Norman Zhang]

Hi,

I've a dual WAN router, currently some of my servers are bound with 
static IPs to ISP1. I like them to remain available on ISP2 if ISP1 goes 
down. Do I need dynDNS service for this? Or I can type in 2 different 
IPs for 1 serivce.

e.g.,

1.2.3.4 IN www.example.com #ISP1
2.3.4.5 IN www.example.com #ISP2.

But internet may still resolve to 1.2.3.4 despite ISP1 being down. May I 
ask what the best way to go about this?

Regards,
Norman Zhang