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OpenConnect VPN on Mac OS X

Unfortunately, the Cisco AnyConnect client for Mac conflicts with Pow. And by "conflicts", I mean it causes a grey-screen-of-death kernel panic anytime you connect to the VPN and Pow is installed.

As an alternative, there is OpenConnect, a command-line client for Cisco's AnyConnect SSL VPN.

Here's how to get it set up on Mac OS X:

  1. OpenConnect can be installed via homebrew:

     brew update
     brew install openconnect
    
  2. Install the Mac OS X TUN/TAP driver

  3. (Optional) Running openconnect requires sudo, presumably because it affects resolution of DNS. So, I added password-less sudo ability for the openconnect command.

     sudo visudo -f /etc/sudoers
    

And added this line:

    %admin  ALL=(ALL) NOPASSWD: /usr/local/bin/openconnect
  1. (Optional) When connecting to your SSL VPN, openconnect may complain about a "self-signed certificate" being in the chain and force you to explicitly accept it every time. The self-signed cert is actually the root certficate and (hopefully) is one with implicit trust (i.e. trusted by browsers), so we can safely trust it by specifying the CA file after exporting it from KeyChain:

  2. Determine the name your root certificate (i.e. visit your SSL VPN in Chrome, click the green lock, click "Certificate Information") Find Certificate Information Observe Root Certificate

  3. Open the Keychain Access App

  4. Search the "System Roots" keychain to find your root certificate and select it Keychain Access

  5. File > Export Items... the certificate as a .pem file somewhere on your hard drive (I put it in ~/.ssh/<certificate name>.pem

  6. Connect!

     sudo openconnect --user=<VPN username> --cafile=<.pem file from step 4.3> <your vpn hostname>
    

    The only thing you should be prompted for is your VPN password. I added the command to my aliases file.

  7. To disconnect, just Ctrl-c in the window where you started the VPN connection.

Note

I had an incident after an unclean VPN exit where later the VPN hostname could not be found. I guess the DNS resolver was messed up. I was forced to reboot to fix it so I could reconnect to the VPN.

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