Configuring the PE Console to Use a Custom Diffie-Hellman File

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The “Logjam Attack” (CVE-2015-4000) exposed several weaknesses in Diffie-Hellman (DH) key exchange, a commonly used method for encrypting and negotiating secure Internet connections via shared keys. Diffie-Hellman key exchange is used by many Internet protocols, including HTTPS, SSH, and IPsec, SMTPS. For reference, see

To help mitigate the “Logjam Attack,” PE ships with a pre-generated 2048 bit Diffie-Hellman param file.

In the case that you don’t want to use the PE default DH param file, the following procedure shows how to generate your own.

To generate a custom DH param file:

Note: In the following procedure, <PROXY-CUSTOM-dhparam>.pem can be replaced with any file name, except dhparam_puppetproxy.pem, as this is the default file name used by PE.

  1. On your PE console server, (for a mono install, this is the same node as a the Puppet master), run the following command:

    /opt/puppetlabs/puppet/bin/openssl dhparam -out /etc/puppetlabs/nginx/<PROXY-CUSTOM-dhparam>.pem 2048

    Note: This step may take several moments to complete.

  2. On your Puppet master, edit your Hiera defaults file (the default location is /etc/puppetlabs/code/environments/%{environment}/hieradata) so that it contains the following:

    puppet_enterprise::profile::console::proxy::dhparam_file: /etc/puppetlabs/nginx/<PROXY-CUSTOM-dhparam>.pem
  3. On your PE console server, kick off a Puppet run with puppet agent -t.

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