# File lib/deltacloud/drivers/eucalyptus/eucalyptus_driver.rb, line 128
        def create_firewall_rule(credentials, opts={})
        # only either source groups or cidr IP range can be given, not both;
          if !(opts['groups'].nil?) && opts['groups'].length>0
            ec2 = new_client(credentials)
            opts['groups'].each do |group,owner|
              safely do
                ec2.authorize_security_group_named_ingress(opts['id'], owner, group)
              end
            end
          elsif !(opts['addresses'].nil?) && opts['addresses'].length>0
            ec2 = new_client(credentials)
            opts['addresses'].each do |ip|
              ec2.authorize_security_group_IP_ingress(opts['id'], opts['port_from'], opts['port_to'], opts['protocol'], ip)
            end
          end
        end