One of the ways you can prevent a server from becoming overloaded is to use the Connection Throttling feature of Cloud Load Balancers. Connection throttling basically imposes limits on the number of connections per IP address. This feature helps prevent malicious or abusive traffic to your server and its installed applications.

Configure Connection Throttling

Note: This procedure assumes you're working with an existing load balancer. If you don't have a load balancer yet, create one now using these instructions: Configuring a Load Balancer.

To configure connection throttling:

1. Click Load Balancers at the top of the Control Panel.
2. Click on Actions cog next to your load balancer and select Edit Connection Throttling from the menu.

The following pop-over appears:

4. Enter a value for each option, and then click Save Connection Throttling. The Connection Throttling options are descibed below.

Setting Connection Throttling Options

When configuring connection throttling, you can specify the following options:

Max. Connections

Specifies the maximum number of simultaneous connections to allow from a single IP address. You can specify a value between 1 and 100000.

Threshold

Specifies the level of simultaneous connections from any IP address at which to apply the throttling restrictions defined by the Limit to and Timeframe fields (see below). You can specify a value between 1 and 1000.

Limit to

Specifies the maximum number of new connections allowed from a single IP address in the defined Timeframe (see Timeframe below). Specify a value between 1 and 100000.

Timeframe

Specifies the interval (in seconds) at which the limit for new connections is assessed once the Threshold is reached. Specify a value between 1 and 3600.

The following field is updated automatically based on your settings for the Threshold, Limit to, and Timeframe fields:

Summary

Describes the results that will be produced by your settings for Threshold, Limit to, and Timeframe.

For example, if you enter 25 simultaneous connections from any IP for the Threshold, 25 new connections for Limit to, and 5 seconds for the Timeframe, after 25 simultaneous connections from any IP, your load balancer would only allow a maximum of 25 new connections for a single IP address every 5 seconds.