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Intermittent HTTPS connectivity issues experienced with Network Management Card 2 (NMC2) and Chrome browser version 55 and newer

Issue

Users may experience intermittent HTTPS connectivity issues when using Chrome (web browser) version 55 and newer with APC Network Management Card 2 (NMC2) enabled products. Below is a screenshot of the possible error generated by Chrome, including ERR_SSL_VERSION_OR_CIPHER_MISMATCH or ERR_SSL_OBSOLETE_CIPHER:



Product Line
  • Network Management Card 2 (NMC2) - AP9630/AP9630CH, AP9631/AP9631CH, AP9635/AP9635CH
Devices with an embedded Network Management Card 2 including (but are not limited to): 2G Metered/Switched Rack PDUs (AP84XX, AP86XX, AP88XX, AP89XX, AP7XXXB), Certain Audio/Video Network Management Enabled products, SRT UPS models.

Environment
  • All serial numbers.
  • Users who utilize secure web access (HTTPS) with NMC2 products.
  • Chrome web browser version 55 and newer.

Cause

The errors displayed above are caused by adjustments to which TLS cipher suites are advertised to web servers made recently in Chrome. The manner in which this is done sometimes causes a problem for the NMC2. This problem has not been observed with other popular web browsers such as Internet Explorer 11 or Firefox.
 
Resolution

A HTTPS connection to the NMC2 within Chrome v55 will often be successful upon creating a new session or refreshing the page a few times. A new session can be created by entering the hostname or IP address of the NMC2 in a new browser tab or window. Make sure not to include any NMC session related information after the URL upon establishing a new connection to the NMC2.
 
Example of a NMC2 URL where session information has been created: https://10.15.37.29/NMC/QQhmFGb0wTawuK7wF7gPqA/logon.htm
 
Proper URL to use when attempting to create a new session in a new browser tab or window: https://10.15.37.29

 
A fix to avoid this problem with Chrome will be available in a future NMC2 firmware version. This knowledge base article will be updated with specifics when available.

Alternatively, another unaffected web browser such as Firefox or Internet Explorer 11 can be used temporarily to avoid the problem.
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