Book Image

Troubleshooting NetScaler

By : Raghu Varma Tirumalaraju
Book Image

Troubleshooting NetScaler

By: Raghu Varma Tirumalaraju

Overview of this book

NetScaler is a high performance Application Delivery Controller (ADC). Making the most of it requires knowledge that straddles the application and networking worlds. As an ADC owner you will also likely be the first person to be solicited when your business applications fail. You will need to be quick in identifying if the problem is with the application, the server, the network, or NetScaler itself. This book provides you with the vital troubleshooting knowledge needed to act fast when issues happen. It gives you a thorough understanding of the NetScaler layout, how it integrates with the network, and what issues to expect when working with the traffic management, authentication, NetScaler Gateway and application firewall features. We will also look at what information to seek out in the logs, how to use tracing, and explore utilities that exist on NetScaler to help you find the root cause of your issues.
Table of Contents (17 chapters)
Troubleshooting NetScaler
Credits
Notice
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

HTTP changes that occur when using AppFirewall


AppFirewall needs to modify packets in order to detect any sort of tampering. In addition to this, enabling certain protections requires AppFirewall to drop parts of the Server response (such as credit cards and other sensitive data) or alternatively transform them (such as keywords) so that special characters are rendered harmless. In this section, let's examine these changes:

  • One of the first changes you will notice if using features that require sessionization is that AppFirewall adds session cookies to the application's own cookies.

    AppFirewall Session Cookie when using Advanced Profiles

  • When Advanced Protections are enabled, AppFirewall also removes caching headers so that instead of a conditional response, a full response is received. This is needed to allow AppFirewall to understand the context of the data being exchanged and drop the response if needed. This does however mean that you will see more requests to the backend servers when using...