Cross-Account Route 53 Private Hosted Zone

Prerequisites

• Admin access to both AWS accounts

• VPC ID from Account B

• Hosted Zone ID from Account A

• AWS CLI configured with profiles for both accounts

Implementation Steps

1. Account A - Create Authorization

# Get Hosted Zone ID
aws route53 list-hosted-zones --profile account-a

# Create Authorization
aws route53 create-vpc-association-authorization \
    --hosted-zone-id <HOSTED_ZONE_ID> \
    --vpc VPCRegion=us-east-1,VPCId=<VPC_ID> \
    --profile account-a

2. Account B - Create Association

# Associate VPC with Hosted Zone
aws route53 associate-vpc-with-hosted-zone \
    --hosted-zone-id <HOSTED_ZONE_ID> \
    --vpc VPCRegion=us-east-1,VPCId=<VPC_ID> \
    --profile account-b

3. Account A - Clean Up Authorization

# Delete Authorization (after association is complete)
aws route53 delete-vpc-association-authorization \
    --hosted-zone-id <HOSTED_ZONE_ID> \
    --vpc VPCRegion=us-east-1,VPCId=<VPC_ID> \
    --profile account-a

CloudFormation Implementation

Account A Template

Resources:
  VPCAuthorizationRule:
    Type: 'AWS::Route53::HostedZoneAuthorizationRule'
    Properties:
      HostedZoneId: !Ref HostedZoneId
      VPC:
        VPCId: !Ref TargetVPCId
        VPCRegion: !Ref TargetVPCRegion

Parameters:
  HostedZoneId:
    Type: String
    Description: Private Hosted Zone ID
  TargetVPCId:
    Type: String
    Description: VPC ID from Account B
  TargetVPCRegion:
    Type: String
    Description: Region of VPC in Account B

Account B Template

Resources:
  VPCHostedZoneAssociation:
    Type: 'AWS::Route53::HostedZoneVPCAssociation'
    Properties:
      HostedZoneId: !Ref HostedZoneId
      VPCId: !Ref VPCId
      VPCRegion: !Ref 'AWS::Region'

Parameters:
  HostedZoneId:
    Type: String
    Description: Private Hosted Zone ID from Account A
  VPCId:
    Type: String
    Description: VPC ID in Account B

Verification Steps

1. Test DNS Resolution:

# From EC2 instance in Account B
nslookup db.example.com
dig db.example.com

1. Check VPC Associations:

aws route53 get-hosted-zone \
    --id <HOSTED_ZONE_ID> \
    --profile account-a

Troubleshooting

1. DNS Resolution Issues:

   • Verify DHCP options set

   • Check security groups

   • Confirm VPC DNS attributes

2. Authorization Issues:

   • Verify IAM permissions

   • Check account IDs

   • Confirm VPC ID and region

3. Association Issues:

   • Maximum VPC associations (50)

   • Region compatibility

   • VPC DNS settings

Security Considerations

1. IAM Policies

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "route53:CreateVPCAssociationAuthorization",
                "route53:DeleteVPCAssociationAuthorization"
            ],
            "Resource": "arn:aws:route53:::hostedzone/*"
        }
    ]
}

1. Network Access

   • Enable DNS hostnames

   • Enable DNS resolution

   • Configure proper NACL rules

Monitoring

1. CloudWatch Metrics

   • DNS queries

   • Resolution success rates

2. CloudTrail Logs

   • API activity

   • Authorization changes

Cost Considerations

• Route 53 hosted zone charges

• DNS query charges

• Data transfer costs

Best Practices

1. Clean up authorizations

2. Use infrastructure as code

3. Implement proper monitoring

4. Document VPC associations

5. Regular testing