Hello we have a network topology designed to eliminate single point of failures at most places in our layer 2 and 3 design.
We also have two DIA internet circuits (different ISP)designed to fail-over from primary link to secondary link if we have issue with one firewall or ISP circuit. The monitoring is done via ping between firewalls and next hops of each ISP.
This works well except when we have an issue with our primary ISP (lets call it ISP1) when connection is not down, but provider is having performance issues with negatively impacts the Web Portal access from external customers.
This Web portal has an IP address with ISP1.
What would be the best solution to having a secondary IP address from ISP2 also be able to respond to Web traffic from Internet to Web portal on our DMZ?