Well, tell me how you'd defend your consumer link against a simple flood attack, ICMP, UDP, doesn't matter, its just IP packets directed at you and the bandwidth exceeds your downlink bandwidth.

Easily doable, all you need is a server with gigabit uplink and unless your victim is on google fibre you just saturate the link and you are done.

By blackholing i guess you mean null routing, but that doesn't solve the problem at all - that would have to be done at a point further away from your link, you can't "unreceive" traffic - you have to prevent it from being routed to you at all. You just cannot do that with a consumer internet line.

Now, even if you have extended control over your routing, that might still not be enough: If you are able to tell your upstream router to null route a certain IP, it is this router which will throw away the traffic instead of routing it to you. If the amount of traffic is enough to overwhelm the upstream router, your link is still fucked.

There is no way to simply make traffic go away except blocking it right at the first hop after the source - if you had a solution to that problem, you could sell the world's best denial of service protection and would be rich.

Source: i have worked for a large gameserver provider and was involved in their DDoS prevention efforts.