PowerCLI 6.3 R1 unable to connect to vCenter after TLS change

I recently upgraded my lab to vSphere 6.0 Update 3 and then used the vSphereTLSReconfigurator to only allow TLSv1.2 as described in this KB article https://kb.vmware.com/kb/2148819. After completing this change, I noticed that my PowerCLI 6.3 R1 machine could no longer connect to vCenter (although my machine with PowerCLI 6.5 was working fine). The specific error encountered was:

connect-viserver : 3/5/2017 3:47:53 PM  Connect-VIServer                The underlying connection was closed: An unexpected error
occurred on a send.
At line:1 char:1
+ connect-viserver vcsa-01a -user administrator@vsphere.local -p ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [Connect-VIServer], ViError
    + FullyQualifiedErrorId : Client20_ConnectivityServiceImpl_Reconnect_WebException,VMware.VimAutomation.ViCore.Cmdl

I found this KB article: Enabling the TLSv1.1 and TLSv1.2 protocols for PowerCLI https://kb.vmware.com/kb/2137109 which solved my issue. I created a 32bit DWORD named “SchUseStrongCrypto” in the HKLM\SOFTWARE\Microsoft\.NETFramework\v4.0.30319 key and set the value to 1. Even using the 64bit version of PowerCLI, this DWORD was all that I needed to resolve my issue.

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3 Responses to PowerCLI 6.3 R1 unable to connect to vCenter after TLS change

  1. Alan Renouf says:

    Any reason you didnt update to PowerCLI 6.5 R1?

  2. I actually had to install PowerCLI 6.3 to test this out — someone had asked me what would happen with PowerCLI if only TLSv1.2 was allowed. I tested with PowerCLI 6.5 and everything worked as expected. I then tried with one rev back to make sure that worked as well. When it didn’t I did a bit of searching and found the KB article that did the trick. Figured I’d share in case anyone else had a similar issue.

  3. Alan Renouf says:

    Thanks, I just wanted to make sure your readers knew that we always recommend installing the latest version as PowerCLI 6.5 R1 is backwards compatible to vSphere 5.5! Thanks for the post.

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