Web application sessions hang when going through ZTNA

Products

• Symantec ZTNA

Issue/Introduction

SAC admin has created a number of different Web applications.

SAC users accessing one such Web application (Confluence) across multiple tabs.

When browsing in one tab, users would often notice that the second tab opened to the same application would show a spinning wheel as highlighted below:

The SAC Web application appears to hang while another thread is working on it.

When the Application is of boarded from SAC, users never see any hanging. 

Environment

SAC/ZTNA.

Web application.

Multiple ZTNA connectors exist for the same deployment.

Cause

Requests are load balanced between the ZTNA site connectors, without any stickiness, causing the application session to hang.

Resolution

Make sure that the Web applications defined 'enforce session stickiness by IP' as shown below.

Additional Information

Looking at the HAR file when the issue happens, some cookies named LRMTD_* are being sent with requests to the Web application. This LRMTD_* cookie is only set when you load balance across multiple connectors.

When this happens, the Web requests can be hitting the back end app from different egress IP addresses, and causing the Application to fail.

When enabling session stickiness, all requests into the back end Web application from a user will be seen as coming from the same egress IP address.