I have two internet connections. The cables from the two ISP's (dhcp; 1-10/10 Mbit; 2-20/20Mbit connection) are on two interfaces: eth0 and eth1. On eth3 there is a Gbit switch and on the switch there are many clients.
How do I configure the Dual-Wan?
I mean I don't want that the clients get notice of that one of the ISP has failed, and "not serving internet"!
So if a client runs
ping 18.104.22.168 and the cable of one of the ISP is torn apart because of a yellow monster :) then there would be no ping outage.
Any Linux-based OS would do (or even *BSD!)