Best way to block spambots in htaccess

[ijb]

I would like to block Russian Federation, China and Ukraine spam as well as semalt and buttonsforwebsite. I have come up with the following code, what do you think?

For the countries:

BLOCK COUNTRY DOMAINS

RewriteCond %{HTTP_REFERER} .(ru|cn|ua)(/|$) [NC] 
RewriteRule .* - [F]

And for buttons-for-website.com and semalt-semalt.com:

BLOCK REFERERS

RewriteCond %{HTTP_REFERER} (semalt|buttons) [NC] 
RewriteRule .* - [F]

or should it be:

BLOCK USER AGENTS

RewriteCond %{HTTP_USER_AGENT} (semalt|buttons) [NC] 
RewriteRule .* - [F]

Could I add (semalt|buttons|o-o-6-o-o|bestwebsitesawards|humanorightswatch) or is that too many?

[donford]

Hi

I think you're on the right track.

A very good blog post by Jared Gardner has recently addressed this question on the Moz Blog.

Hope it helps,

Don