Multiple WAN addresses from different ISPs on a single interface


I am setting up a VyOS instance with a WAN (eth0) and a LAN (eth1). On WAN side, there are multiple static addresses (from three different ISPs) available:

ISP 1: via via via

ISP 2: via via via

ISP 3: via

I have successfully added all the addresses to eth0 and added a default route ( via for ISP 1. Now, I can ping all three addresses of ISP 1 from another host on the Internet, but not addresses of ISP 2 nor ISP 3. I understand this is because the reply traffic are being incorrectly sent thru ISP 1 gateway. How could I make the reply traffic sent thru the correct gateway?


Oh I managed to figure it out: Just add another two default routes for ISP 2 and ISP 3, and all addresses are reachable from the Internet.

I used to though multiple routes would cause problems but they seem to work well. I repeatedly curl and I can see different IP addresses from the three ISPs.