last updated 2015.05.22 1645 UTC changelog
Who isn't fed up with the amount of spam from Chinese and Korean net blocks? China is not only a major spam source, but also provides bullet proof web and DNS hosting to the vast majority of p0rn, pillz, and other seedy web sites referenced by the URL's in spam (spamvertising). They know this, but do not care as foreign $$ are more important to them than your mail box is. Ironic that a country which goes to great lengths to censor net p0rn from it's own people is by far the world leader in hosting such sites.
In addition to the greed factor, there seem to be far too many sysadmins in China and Korea who are lacking in even the most basic technical competence of securing a mail server from unauthorized relay or proxy abuse. In most cases, you're lucky if their abuse addresses even work...much less get read or acted on.
I decided in April, 2002 that all email from both Korea and China would no longer be accepted by any of my or my clients' mail servers. I started compiling lists of all net blocks assigned to Korea and China to achieve that end and have honed the listings to what I believe to be the most current, comprehensive, and accurate listings of their kind. I continue to add to or change it on a near daily basis as new net bocks are assigned to either country.
Using the lists on this site will result in the complete blocking of all email transactions from any node in net space assigned to China or Korea. If you run a business that depends on mail from those countries, you should probably either not use this data or investigate whitelisting the specific Chinese or Korean servers you need to get email from.
note: although it might be tempting to blacklist an entire /16 or larger when it seems as if Korea or China is using the entire net block, you stand the risk of blocking friendlies (New Zealand, Australia, Japan, etc.) in the process. I've taken great care to identify the starts and ends of all the listed blocks.
Here are the goods!: http://www.okean.com/thegoods.html