DNS Server Security Group.

AWSTemplateFormatVersion: '2010-09-09'
Description: ''
Resources:
  SecurityGroup:
    Type: 'AWS::EC2::SecurityGroup'
    Properties:
      GroupDescription: A security group that allows inbound DNS traffic (TCP and UDP port 53).
      VpcId: ''
      SecurityGroupEgress:
        - FromPort: -1
          ToPort: -1
          IpProtocol: '-1'
          Description: ''
          CidrIp: 0.0.0.0/0
      SecurityGroupIngress:
        - FromPort: 53
          ToPort: 53
          IpProtocol: udp
          Description: Allow DNS traffic - UDP 53
          CidrIp: ''
        - FromPort: 53
          ToPort: 53
          IpProtocol: tcp
          Description: Allow DNS traffic - TCP 53
          CidrIp: ''
      GroupName: allow-dns-traffic
Parameters: {}
Metadata: {}
Conditions: {}