Nigerian IP Addresses

Where can I get an up-to-date list of Nigerian IP's

[glitterball]

I have a site with an internal mail system for the site's users (a bit like sticky mail here).

Unfortunately this system is being abused by Nigerian 419 scammers, who are signing up to the site and sending these messages to other users.
As soon as we are notified of these messages, we remove them and ban the offending user, however it is becoming a pain.

What I want to do is ban anyone with an IP address in Nigeria, so I'm looking for an up-to-date list of IP addresses from that country.

[MrWumpus]

There's a related thread here: [webmasterworld.com...]

Also note, many 419 scammers will appear to be coming from Israel because there is a major sattelite ISP from Israel that serves West Africa.

[keyplyr]

Almost futile to block the Nigerians, since as noted, they can bounce their connections around easily. There's also a large Nigerian community in London (among other places) who run servers themselves, and guess who their clients are?