Hello,
I migrated from Apache to nginx and I have a small problem.
I'ld like to block users behind proxies or users which use "strange" headers. Of course it's impossible to block all, but in Apache I could use that:

RewriteCond %{HTTP:VIA} !^$ [OR]
RewriteCond %{HTTP:FORWARDED} !^$ [OR]
RewriteCond %{HTTP:USERAGENT_VIA} !^$ [OR]
RewriteCond %{HTTP:X_FORWARDED_FOR} !^$ [OR]
RewriteCond %{HTTP:PROXY_CONNECTION} !^$ [OR]
RewriteCond %{HTTP:XPROXY_CONNECTION} !^$ [OR]
RewriteCond %{HTTP:HTTP_PC_REMOTE_ADDR} !^$ [OR]
RewriteCond %{HTTP:HTTP_CLIENT_IP} !^$
RewriteRule ^(.*)$ - [F]

Is it possible to make similar rewrites/conditions for nginx? I read about Access and Geo Modules, but I don't sure what should I use.