i want to know what is the best practice of the following
we implementing "Live DR", so we connecting Main site with DR Site by Layer2 in all internal vlans. and also the cluster FW will be 3rd and maybe also 4th members at the DR Site. so Internet/Dmz Cluster will be ni Main and in DR Site.
my quesion is about the Isp's side/Default route site.
what is the best practice here?
do i have to do Layer 2 Line between Isps between sites (to my knowledge it's must for the cluster), or can i use different ISPs, or same ISPs but with different lines (and also different public IP subnets)
and let's assume i have L2 between ISPs between sites, what will happend if the Internal Sync /other vlans disconnected between sites, and GWs become active together in Main Site and DR Site, so the ISP will see the same VIP alive in both sites, and it won't work.
how it's usually implemented ?
i attached draw for general architecture.