Book Image

Mastering NetScaler VPX

By : Marius Sandbu, Andy Paul
Book Image

Mastering NetScaler VPX

By: Marius Sandbu, Andy Paul

Overview of this book

Citrix NetScaler is one of the best Application Delivery Controller products in the world. The Application Delivery Controllers are commonly used for load balancing purposes, to optimize traffic, and to perform extra security settings. This book will give you an insight into all the available features that the Citrix NetScaler appliance has to offer. The book will start with the commonly used NetScaler VPX features, such as load balancing and NetScaler Gateway functionality. Next, we cover features such as Responder, Rewrite, and the AppExpert templates, and how to configure these features. After that, you will learn more about the other available Citrix technologies that can interact with Citrix NetScaler. We also cover troubleshooting, optimizing traffic, caching, performing protection using Application Firewall, and denying HTTP DDoS attacks for web services. Finally, we will demonstrate the different configuration principles real-world Citrix NetScaler deployment scenarios.
Table of Contents (15 chapters)
Mastering NetScaler VPX™
Notice
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Preface
Index

Global Server Load Balancing


Global Server Load Balancing (GSLB) allows us to load-balance services across different geographical regions. For instance, large organizations such as Facebook, eBay, and Microsoft use this technology to load-balance their web services. This might be for proximity reasons, because a user might be redirected to the closest available resource, or to keep redundant services available in case of datacenter failures.

So the main purposes for GSLB are:

  • Performance; user proximity to the closest available resource

  • Disaster recovery, where multiple sites can be grouped as primary and standby

  • Load balancing resources between different multiple locations

GSLB is based upon the use of DNS. So for instance when a user wants to go to www.citrix.com, that user's DNS client will do a number of queries against the different DNS servers, until it gets a response from an authoritative source for that domain. An example might be where NetScaler, which is the authoritative nameserver...