How to block a specific user agent in nginx config

Question

How do I block a user agent using nginx. so far I have something like this:

if ($http_user_agent = "Mozilla/5.0 (Linux; Android 4.2.2; SGH-M919 Build/JDQ39) AppleWebKit/537.22 (KHTML, like Gecko) Chrome/25.0.1364.169 Mobile Safari/537.22") {
return 403;}

this is from a similar thread on this stack overflow.

I run nginx as a reverse proxy for cherrypy server. I intend to filter a certain user agent using nginx alone but the above code doesn't work on my server.

is that the correct way to do this? It wasn't included in any block in the nginx config. Should I add it to the "http" block or the "server" block

Answer 1

in order to block the specific user agent I included this code in the "server" block:

if ($http_user_agent = "Mozilla/5.0 (Linux; Android 4.2.2; SGH-M919 Build/JDQ39) AppleWebKit/537.22 (KHTML, like Gecko) Chrome/25.0.1364.169 Mobile Safari/537.22"){
    return 403;
}

and it worked as expected.

Answer 2

If's are evil - use the map directive.

See Nginx Ultimate Bad Bot Blocker