My router logs were full of similar 'probes' about 12 months ago.
Lasted for a couple of weeks then disappeared of their own accord.

BTW. I don't think Zen should intervene; not their role and the 'probes' are harmless as far as I can judge.

Router is doing its job, so leave it to get on with it.

Well I wouldn't go as far as blocking the entire Asia Pacific region, but China wouldn't be a problem to me.

Hope you don't need any motherboard/other chipset drivers.

You could use something like 'Peer Guardian' (or any other firewall capable of handling huge lists) along with a list of region-specific address ranges like this site provides.

Seems a bit pointless to me, though (for the sake of blocking some irrelevant port probes at least ).