The easiest way to deal with the usual suspects is to just block the entire countries network range(s). There really is no reason they should be connecting to your home router anyway, and you lose nothing from blocking them.
Sure their packets will still hit your router, but if they are dropped immediately at least you're not wasting a syn-ack on them.
I, temporarly, banned some ip range. I didn't find a source for pinpointing countries; though I am interested. Could you point me to some sources which, deterministically, resolve to some countries? To my knowledge you can not reliably identify countries by ip since this would be dependent on DNS servers. Though I am just a application programmer!
Thanks in advance.