How Project Shield works
Project Shield is a free service that helps protect websites from distributed denial of service (DDoS) attacks. A DDoS attack is an attempt to make your website unavailable by overwhelming it with traffic from multiple sources.
Project Shield works by filtering out harmful traffic and passing safe traffic to your website server.
How Project Shield protects your site from DDoS
Project Shield is a reverse proxy: Project Shield servers receive traffic requests on your website's behalf and then sends safe traffic to your website's server.
This protects your site against distributed denial of service (DDoS) attacks in two ways:
- It filters harmful traffic. Project Shield filters out harmful traffic using Google’s technology and DDoS tools. If someone tries to take your website down with a DDoS attack, Project Shield can identify and block harmful traffic so your website stays up and running.
- It absorbs traffic through caching. Project Shield can cache — or save — versions of your content to serve to website visitors. This reduces traffic requests to your website server and absorbs potential DDoS attacks. For example, if many visitors want to view the same content on your website (or, in a DDoS attack, an attacker is trying to overwhelm your website with traffic), Project Shield will fetch the content from your website's server once and then serve a cached copy repeatedly.
Who can apply for Project Shield?
News websites, human rights websites, and elections monitoring websites are eligible to apply. Project Shield individually reviews applications and invites eligible applicants on a rolling basis.
Learn more about applying for Project Shield.
How do you set up Project Shield?
If you apply and are invited to Project Shield, setup involves the following steps:
- Tell us which websites to protect.
- Tell us where to find the web server that hosts your content, either with an IP address or a hidden host name.
- Change your Domain Name System (DNS) records to point traffic to Project Shield’s servers.
Learn more about setting up Project Shield.