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

RADIUS protocol


In NetScaler environments, RADIUS is commonly used for two-factor authentication, and is the protocol to choose when integrating with One Time Password (OTP) servers.

The ports used by Radius are as follows:

  • UDP 1812: Authentication

  • UDP 1813: Radius Accounting

  • UDP 1645 and 1646: Legacy ports for the same purpose that some servers might use

Authentication flow

When authenticating, the exchange will start with an access-request from the NetScaler to the RADIUS server. To this, the server can respond with one of three responses, given as follows:

  • Access-Accept: All is good and the User is through

  • Access-Reject: Either the RADIUS server parameters, such as the secret, are not configured correctly, or the User credentials are incorrect

  • Access-Challenge: This is what you will see when using an OTP solution, the NetScaler has received a prompt for additional credentials

The following is a screenshot of a successful RADIUS (Access-Accept) authentication:

Troubleshooting RADIUS authentication...