Q: What types of traffic can be monitored for Rate Limiting?

A: HTTP, TCP, and DNS requests are supported for Rate Limiting.

Q: Can I restrict all my client connections to a specific bandwidth limit of 200K per client connection?

A: Yes. All limits are enforced through a designated action such as DROP, RESET, REDIRECT, or CACHE, when the limit or threshold is reached. Therefore, rate limiting feature takes an action to enforce the limit.

For example, if you apply rate limiting on an HTTP virtual server and limit it to 200K per client connection with a policy or limit identifier using "client.ip.src" with the "maxbandwidth" option, then the policy invokes the designated action on all subsequent requests when a connection reaches 200K.

In other words, if DROP is configured as the action, then all subsequent requests are dropped. If REDIRECT is configured as the action, then the subsequent requests are redirected to an alternate location as long as the limit is exceeded.

Q: How do I configure a NetScaler appliance, if I only want to limit all my traffic to a certain bandwidth level, but still allow the traffic through the entity without redirecting, dropping, or resetting the subsequent requests?

A: NetScaler Rate Limiting does not currently have the ability to control bandwidth without taking a designated action. Therefore an external network device such as a Packet Shaper is required to govern bandwidth utilization in this manner.

Q: Are there any alternatives to use the Rate Limiting feature, if there is a subset of clients that are high traffic consumers for an entity such as Load Balancing virtual server?

A: Rate Limiting can be used to limit a subset of clients using subnet or IP address to restrict them to the entity based on bandwidth as described. The rate limiting feature will not be applied to the clients outside that range.

Another option would be to utilize Content Switching feature to route high bandwidth consumers to a separate Load Balancing virtual server, such that it does not impact other client connections.

Additional Resources

• CTX134009 - How to Implement Rate Limiting on a NetScaler Appliance by Using the Responder Feature
• Citrix Documentation - Rate Limiting on NetScaler
• CTX128992 - How to Configure the Responder Feature to Display User Specific Messages when Rate Limit for Active Connections Exceeds on a NetScaler Appliance