# Using Cloudflare to defend against DDoS attacks

> Protect your website from DDoS attacks with Cloudflare's Under Attack mode and by whitelisting trusted IP addresses.

Source: https://helpcenter.ruachost.com/add-ons/cloudflare/using-cloudflare-to-defend-against-ddos-attacks/

## Using Cloudflare to Protect Your Site from DDoS Attacks

Learn how to defend your website against DDoS (distributed denial-of-service) attacks using Cloudflare’s "Under Attack" mode and IP whitelisting.

> **Note:**
For instructions on activating Cloudflare for your account, see Cloudflare’s setup guide. For full details on configuring Cloudflare, consult the Cloudflare documentation.

### **Understanding Cloudflare DDoS Protection**

DDoS attacks involve multiple devices overwhelming a website with traffic, causing slowdowns or downtime. Cloudflare’s distributed network absorbs this traffic, reducing the impact of attacks.

For additional protection, you can enable "Under Attack" mode. This security feature checks incoming traffic before allowing access. Legitimate visitors see a brief interstitial page (about five seconds) while Cloudflare verifies the connection.

Alongside "Under Attack" mode, you can whitelist trusted IP addresses to further protect your site.

### **Enabling "Under Attack" Mode**

1. Log in to your Cloudflare account.
2. In the left sidebar, click **Websites**, then select your domain.
3. In the right sidebar under **Quick Actions**, toggle the **Under Attack Mode** slider.
4. To disable it, click the slider again and select the desired security level.

**Note:** After an attack, using the **High** security level challenges visitors who have shown suspicious activity in the past 14 days. You can lower the level once the threat subsides.

### **Whitelisting IP Addresses**

Whitelisting allows only trusted IPs to access your site, adding another layer of security.

1. Open the `.htaccess` file in `/home/username/public_html/` using cPanel File Manager or SSH (replace `username` with your account username).

   - If the file doesn’t exist, create it.
2. Add the following lines at the top:

   ```
   order deny,allow
   deny from all
   ```
3. Copy Cloudflare’s IPv4 addresses from <https://www.cloudflare.com/ips-v4> and paste them after `deny from all`, one per line, prefixed with `allow from`.
4. To add additional trusted IPs (e.g., home or office), use the same `allow from IP_address` format.

**Tip:** To find your IP address, visit [http://ipfinder.us](http://ipfinder.us/).

Save the `.htaccess` file. Your whitelist is now active.

**Note:** To remove whitelisting, either comment out lines with `#` or delete them.

### **More Information**

For general Cloudflare guidance, visit [https://www.cloudflare.com](https://www.cloudflare.com/).