[nginx blocker](https://github.com/crowdsecurity/cs-nginx-blocker) will check every unknown IP against the database before letting go through or serving a *403* to the user, while a [netfilter blocker](https://github.com/crowdsecurity/cs-netfilter-blocker) will simply "add" malevolent IPs to nftables/ipset set of blacklisted IPs.
You can explore [available {{blockers.name}} on the hub]({{hub.plugins_url}}), and find below a few of the "main" {{blockers.name}}.