Under a DDoS attack?

A distributed denial-of-service (DDoS) attack is where a large number of computers or devices, usually controlled by a single attacker, attempt to access a website or online service all at once. This flood of traffic can overwhelm the website's origin servers, causing the site to slow down or even crash.

sequenceDiagram;
    participant User;
    participant Website;
    participant Server;
    participant Botnet;
    User->>Website: Requests to access site
    Website->>Origin Server: Processes user requests
    Botnet->>Origin Server: Sends a flood of traffic
    Origin Server-->>Website: Slows down due to traffic overload
    Origin Server-->>User: Unable to respond to user requests

Common signs of an attack

Common signs that you are under DDoS attack include:

• Your site is offline or slow to respond to requests.
• Unexpected spikes appear in the graph of Requests Through Cloudflare or Bandwidth in your Cloudflare Analytics app.
• Strange requests appear in your origin web server logs that do not match normal visitor behavior.

Note

If you are currently under DDoS attack, refer to our guide on responding to a DDoS attack.