We have 2 remote offices, running ROS 6, each site has 2 ISPs, with simple recursive failover config without routing marks, etc..
Both sites have same ISP as “ISP1”, but on second site it is not used as a primary one.
The issue we have: “ISP1” is connected to both sites via DHCP client, where on both sites we receive the same gateway, DNS, and the same /24 subnet, but with different white IPs. On both sites we can see all the clients on /24 subnet of ISP1. Because of it when we send traffic to DDNS from site A, where another ISP is used as a primary one but ISP1’s DHCP client is working, to site B, where ISP1 is primary, site A ignores that ISP2 has active route to 0.0.0.0/0 and sends traffic through ISP1. In result we have connection issues between sites with the same ISP with IP in /24 ISP’s same subnet.
Is it an issue we shall address to ISP, or is it our fault with routing ?