One of my WP blogs is getting lots of comment spam recently and seems like my Akismet simply cant stop them.. After doing some investigation I found that 90% of these comments came from 1 country, so I just wonder is there any way to block all the comments which come from certain countries? Thanks!
Can't you use the ReCaptcha plugin? I use that and have never had a problem with spam. It is the tool that makes users type in the words they see before they can comment.
I would outright keep them out of your site. go to your .htaccess deny from 1.2.3.4 Replace the 1.2.3.4 with their IP and they can no longer access your site.
In my opinion, you should use recaptcha plugin for wordpress for this purpose and after that you have not to block several IP's.
I have just installed this: http://wordpress.org/extend/plugins/wp-ban/ It works amazing, simply enter the IP Address of the Spammer and they will not be able to visit your blog again. After they are banned you can view how many times they have tried to visit the site.