Unable to see exception page on Web Browser when blocking certain application operations with Edge SWG or ProxySG

Products

• ISG Proxy
• ProxySG Software - SGOS
• Advanced Secure Gateway Software - ASG

Issue/Introduction

You have configured a policy to block Web Application Operations such as Upload or Post & provide an exception page for this operation. You notice that the operation is blocked with the message shown by the individual webpage but the Exception page is not displayed. HAR analysis further shows that the exception page was sent by the ProxySG.

We will use 'LinkedIn' 'Post Messages' application operation block as an example to demonstrate. The block rule with exception code & page is delivered to the web browser but you do not see the complete exception page, instead a simple error message as below:

You want a complete exception page to be displayed on the Web Browser instead as below:

Resolution

This behavior is expected. It is not feasible to display the entire exception page within the message text frame or within sub-URL message windows. This is not a limitation from Edge SWG or ProxySG but a technological limitation within HTTP & the way individual Website's web page rendering & display implementation.