Situation: Two ISP's, need to provide failover redundancy.
It seems like the prevailing wisdom when it comes to Windows servers is "don't multi-home". And whenever anyone asks how to do it properly, you get people asking "why do you need to"? Other suggestions are "use a load balancing router".
Unfortunately, I've tried to use load balancing routers (consumer level, I can't afford high end Cisco's) and they just don't work reliably, and they don't really offer source based routing (or any kind of real policy based routing) to allow specific traffic to use specific internet connections.
The best overall solution in my case is to simply feed both internet connections into my server via seperate NIC's. The problem is that Windows doesn't seem to have a way to do what's called "split-access" routing. Split-access allows multiple interfaces to have their own default gateways so that when a packet comes in from the internet, the response packets can be routed back over the same gateway (instead of the system default gateway).
For more info on split-access read this:
This solution works great for Linux, using iproute2, i can setup split-access and things work great. But in Windows, it always tries to respond to packets that originate from outside the LAN via the system default gateway rather than the gateway of the second net connection. You can't simply add a second default gateway, as this causes all kinds of weird results.
Is there any way in Windows to do something similar to split-access with iproute2 in Linux?
The idea here is that I have two NIC's in the server. I bind my web server to both NIC's with different IP addresses, then I use failover DNS system that will monitor my network connection and switch to the secondary IP (on the second ISP) if the first goes down. Not the best solution, but I can pull it off for a lot less money than alternative solutions.
For DNS failover, i'm considering a solution such as this:
Please don't lecture me about not needing to multi-home, because I cannot afford the equipment to do load balancing properly and consumer level equipment doesn't function reliably for my needs.