Nginx : How to block user agent ?

Problem : Looking for ways to configure Nginx to block certain user agents like crawlers, SEO tools and robots from molesting your website.

Solution : Configure nginx.conf file to instruct Nginx to return 403 status when certain user agents visit the website.

For example:

 vi /usr/local/nginx/conf/nginx.conf

and add these lines under the server block. If you have additional server block for SSL, add the same lines for the server block as well.

 server {
  listen 80;
  if ($http_user_agent ~* (wget|majestic|ahrefs) ) {
 return 403;
  }

Note : ~* means case insensitive blocking. For case sensitive, use ~ instead.

restart nginx

 /usr/local/nginx/sbin/nginx -s reload

In this way, whenever one of these user agents visit your website, it will be given a 403 status.