Senario I have a network lan with 4 vlans going through a 6509 switch. I have a cisco 2921 router that we use as our firewall with Access list. I use access list/nat to route outside IP's to my inside servers. I'd like to add a second ISP with another block of IP's for failover on the same router. I have DNS Failover setup on the WAN side with a 3 party. Just not sure where to start or if this is even possible.