Finally I have failover with recursive routing working (attached). Used mainly Tomas Kirnak approach (many thanks!). I have a question about it. I notice that not always come back to main connection, let say, router goes to isp1 which is main, primary connection, fast but unstable, when missed pings succeed then router goes to secondary, backup connection, and stays there. Eventually changes to primary many times but finally stays on secondary and does not goes back to primary. My question is: Im missing something on my config ? (I do have blackhole route disabled but dont now how to use it), primary connection instability makes router decides not to go back to primary any more ?, How router evaluates routes ?, thanks for answering
Disabling fast route can help you but you need to be more careful about consequences in other hand There is some problem with that and that is why I recommended to use Netwatch instead of check gateway with ping,
You Assume your router has access to your ISP1 but your ISP1 has internal problem so in that case you never switch to the ISP2.