config/initializers/activemerchant_proxy.rb

activemerchant_proxy.rb

unless Settings.activemerchant.proxy.host.blank?

  module ActiveMerchant
    class Connection
      alias_method :http_original, :http
      private
      def http

        proxy = Settings.activemerchant.proxy
        http = Net::HTTP.new(endpoint.host, endpoint.port, proxy.host, proxy.port)
        configure_debugging(http)
        configure_timeouts(http)
        configure_ssl(http)
        configure_cert(http)
        http

      end
    end
  end

end