I went to http://www.iana.org/assignments/ipv4-address-space and grep-ed for APNIC (Asia-Pacific Network Information Center) to get the following list. For the church email site that I support I block wholesale /8 IP address ranges. I assume that for our church we will never get email from an APNIC site.
*snip* Great, if you intend to never correspond with 202/8, 203/8 and 210/8 you just nuked most of New Zealand and a lot of Australia at the same time. You might find that being a _tad_ more specific is useful. Believe it or not, theres a lot of legit business conducted between Australasia and the rest of the world... Mark. (Who has historically had a LOT of trouble convincing some providers that denying comms with New Zealand is a good way to get a whole nation up in arms, especially if you're a big name telco in the US who is dropping IP from a big name telco here...)