title: Cloudformation ipv4 and ipv6 egress
body: <p>I would like to add an alltraffic ipv4 and alltraffic ipv6 outbound rule to my security group. However, Cloudformation keeps building just the ipv6 when i defined both.</p>
  <p>I started with the following code:</p>
  <pre><code>    SecurityGroupEgressAllTrafficipv4:
        Type: 'AWS::EC2::SecurityGroupEgress'
        Properties:
          Description: &quot;Allow all outbound traffic by default&quot;
          GroupId: !Ref &quot;SecurityGroup&quot;
          CidrIp: &quot;0.0.0.0/0&quot;        
          IpProtocol: &quot;-1&quot;
  
      SecurityGroupEgressAllTrafficipv6:
        Type: 'AWS::EC2::SecurityGroupEgress'
        Properties:
          Description: &quot;Allow all outbound traffic by default&quot;
          GroupId: !Ref &quot;SecurityGroup&quot;
          CidrIpv6: &quot;::/0&quot;        
          IpProtocol: &quot;-1&quot;
  </code></pre>
  <p>Since it was only building ipv6, I found this post as reference: <a href="https://stackoverflow.com/questions/51515805/how-to-specify-both-ipv6-and-v4-in-security-groups-in-cloudformation/51886750">How to specify both IPv6 and v4 in Security Groups in CloudFormation?</a>. I tried the format that the commenter posted and was receiving an error: <em>Error: Template format error: Any Properties member must be an object.</em></p>
  <pre><code>    SecurityGroupEgressAllTraffic:
        Type: 'AWS::EC2::SecurityGroupEgress'
        Properties:
          - Description: &quot;Allow all outbound traffic by default&quot;
            GroupId: !Ref &quot;SecurityGroup&quot;
            CidrIp: &quot;0.0.0.0/0&quot;        
            IpProtocol: &quot;-1&quot;
          - Description: &quot;Allow all outbound traffic by default&quot;
            GroupId: !Ref &quot;SecurityGroup&quot;
            CidrIpv6: &quot;::/0&quot;        
            IpProtocol: &quot;-1&quot;
  </code></pre>
  <p>Has anyone attempted this with success? Thanks.</p>