This document provides the resolution for Cisco Integrated Management Controller (CIMC) GUI, which hangs while it is loaded after the Firefox is updated to Version 55 and later.
Cisco recommends that you have knowledge of these topics:
- Cisco UCS C-Series rack servers.
- Cisco Integrated Management Controller (CIMC).
The information in this document is based on Standalone UCS C Series Servers running Firmware 2.0(x) and earlier releases that require Flash Player.
The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, ensure that you understand the potential impact of any command.
Note: When CIMC GUI is accessed, the management client must meet or exceed the minimum system requirements mentioned in CIMC release notes in terms of Browser, Operating System, and Java Runtime Environment (JRE): https://www.cisco.com/c/en/us/support/servers-unified-computing/ucs-c-series-integrated-management-controller/products-release-notes-list.html
This behavior was observed after Firefox update to version 55.0, which was introduced on August 8, 2017.
Mozilla update history displays each successfully installed updates, as shown in the image:
As per the release notes for Firefox 55.0 Release, they made the Adobe Flash plugin click-to-activate by default and allowed only on http:// and https:// URL schemes:
For more information see the Firefox plugin roadmap: https://developer.mozilla.org/en-US/docs/Plugins/Roadmap
While Adobe Flash plugin (Shockwave Flash) within Firefox set to Ask to Activate, it does not give a prompt that the application requires Flash Player after login to CIMC GUI. However, you see a blank rectangle, after this rectangle is pressed, the plugin notification icon appears toward the left end of the address bar, as shown in the image:
If you click the message or the notification icon to activate the plugin, Firefox prompts you with two options:
- Allow Now: Activates Flash only for a single visit.
- Allow and Remember: Activates Flash for all future visits to that site.
Once you allow the plugin, the missing content is loaded normally. (If it doesn't please reload the page and try again).
Problem: CIMC GUI Hangs while it is Loaded
After you enter the username and password, the CIMC page hangs while it is loaded and never proceeds further. CIMC IP is pingable and SSH works fine where you can see that there is a TCP GUI session established as the command show user-session is used. Now TCP 3-way handshake is established fine, but Browser shows the GUI is hung as it is loaded.
Issue is reproducible for CIMC 2.0(x) and earlier releases after you update Firefox Browser to Version 55 and later and if Flash Player is not upto date within the browser.
Note: Issue is not reproducible with CIMC 3.0(x) as it does not require Flash Player.
This image shows the CIMC GUI before you login.
This is the image after you Login.
SSH session to CIMC after login shows a TCP GUI session, which is established as shown in the image, when this command show user-session is used.
While the flash plugin is set to Ask to Activate after the Firefox update to version 55, you can enable the plugin manually through a blank rectangle to display the notification. If you want to run the plugin automatically, change the setting of Shockwave Flash plugin to Always Activate on the Mozilla browser and ensure that Adobe Flash Player is upto date. Then CIMC GUI is loaded fine.
Note: There are three different types of Flash Players: an ActiveX version for Internet Explorer, a Chrome version built into the browser and a plugin version for Firefox.
This is the procedure to enable Adobe Flash Player In FireFox automatically:
Step 1. Open your Firefox browser, on the top-right corner, click the three-bar icon and select Add-ons, as shown in the image:
Step 2. On the left side, click Plugins. Then click Shockwave Flash and select Always Activate, as shown in the image:
Also, ensure that Shockwave Flash Plugin is up to date, in order to do so, navigate to options and select check for updates, as shown in the image:
In order to check if you have the latest version of Adobe Flash, visit this website and check individually for each browser, it shows the current version you have and a table of the latest versions:
CIMC is loaded fine as the flash plugin is enabled manually through the blank rectangle or automatically when the setting is changed to Always Activate. Also ensure that the Shockwave Flash Plugin is upto date.