Error: "browser no longer supports the NPAPI plug-in" or "This Plugin is not supported" ProxySG Advanced Secure Gateway

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Article ID: 169379

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Updated On:

Products

Advanced Secure Gateway Software - ASG ProxySG Software - SGOS

Issue/Introduction

Direct in-browser access to the ProxySG or Advanced Secure Gateway (ASG) Management Console fails with messages "browser no longer supports the NPAPI plug-in" or "This Plugin is not supported".

Access to the ProxySG or Advanced Secure Gateway Management Console fails with messages "browser no longer supports the NPAPI plug-in" or "This Plugin is not supported".

Cause

NPAPI plugin support is required when a browser accesses the ProxySG Management Console or the Proxy tab in the ASG Management Console directly.  Some browsers, such as Google Chrome and Mozilla Firefox, have removed support for the NPAPI plugin.

Refer to following for the status of the NPAPI plugin support amongst browser versions:

Google Chrome:

  • NPAPI plugin support was disabled by default in version 42.  
  • NPAPI plugin support was removed in version 45 and later.

References:


Mozilla Firefox:

  • NPAPI plugin support was disabled by default in version 52.  
  • NPAPI plugin support will be removed in version 53 and later.

References:


Note: Symantec supports browsers unaffected by NPAPI plugin removal that can access the Management Console directly.  See Supported Java, operating system, and browser versions for SGOS and Advanced Secure Gateway

Resolution

A transition from direct, in-browser access, to using Java Web Start for all Management Console activities.  Doing so ensures that any future changes in browser behavior will not impact Management Console accessibility.  For details on using Java Web Start, see Download the Management Console Launcher JNLP file to launch multiple Management Consoles

Workaround

Use the appropriate workaround if the Management Console must be accessed directly using a browser that has removed or disabled support for the NPAPI plugin.

If you are currently running Google Chrome version 42 through 44
NPAPI plugin support was disabled by default in versions 42 through 44.  
To enable NPAPI plugin support:

  1. In the browser address bar, enter: chrome://flags/#enable-npapi
  2. In the Enable NPAPI section, click the Enable link.
  3. At the bottom of the configuration page, click the Relaunch button to relaunch the browser.


If you are currently running Mozilla Firefox version 52
NPAPI plugin support was disabled by default in version 52.  
To enable NPAPI plugin support :

  1. In the browser address bar, enter: about:config
  2. Add new Boolean string "plugin.load_flash_only" and set it to false.
  3. Restart the browser.

Reference: http://www.omgubuntu.co.uk/2017/03/force-enable-firefox-52-npapi-support

NOTE: NPAPI support in Firefox ESR version 52 is not currently compatible with the ProxySG or Advanced Secure Gateway Management Console.