To avoid excessive usage of bandwidth, and protect your site from Denial Of Service attacks, you can limit bandwidth usage for a site and limit the number of simultaneous connections.

Note: To enable users to limit bandwidth in Plesk for Linux, the Plesk administrator must install the support for the Bandwidth Limiter for Apache through Tools & Settings > Updates and Upgrades > Add/Remove Components > Web hosting > Apache > mod_bw. Also, the administrator will need to stop nginx through Tools & Settings > Services management > stop Reverse Proxy Server (nginx). In Plesk for Windows, make sure that QoS Packet Scheduler is working in your system.

To limit bandwidth usage and number of connections to a site:

  1. Go to Websites & Domains and find the site’s domain name.

  2. Click Bandwidth Limiting.

    Note: This command is available only if your hosting provider has turned on the support for bandwidth limiting.

  3. Select the Switch on bandwidth limiting checkbox.

  4. In the Maximum bandwidth usage (KB/S) box, specify the maximum speed, measured in kilobytes per second, that a website can share among all its connections.

  5. Select the Switch on connections limiting checkbox.

  6. In the Connections limited to box, specify the maximum number of simultaneous connections to the site.

  7. Click OK.