NetScaler Gateway™ VPNs

To get a baseline idea of what a successful login and resource access should look like, over the next few pages we will examine the various stages of a NetScaler Gateway VPN session using a Wireshark capture. The intent is to provide you with the knowledge of a known good trace that you can compare against when troubleshooting issues.

We will then follow up with a discussion of the troubleshooting tools and techniques for troubleshooting NetScaler Gateway VPNs.

Examining VPN session launch using Wireshark

VPN session establishment is a multi-step process where the client and NetScaler exchange a number of control messages. To make this exchange easier to digest, let's break this into different phases:

• Phase 1: The EPA exchange

• Phase 2: The authentication exchange

• Phase 3: Post login exchange

Note

To avoid duplication, we will assume the SSL handshake was successful. SSL handshake troubleshooting would be exactly the same as covered in the SSL section of Chapter 2, Traffic...