Route53

Creating a Public DNS Record in Route 53

Overview

Domain expertise for adding or updating a record in a Route 53 public hosted zone so a hostname resolves to a target: an IP address, an AWS resource, or another hostname. Covers the choice between alias and standard records, the zone apex (root domain) constraint, long TXT value handling, and the Evaluate Target Health (ETH) toggle on alias records.

Does not cover routing policies that split or steer traffic (weighted, failover, latency, geolocation), private hosted zones for hybrid networks, domain registration, or health check creation. Those are separate skills.

Execute commands using the AWS MCP server when connected (sandboxed execution, audit logging, observability). Fall back to the AWS CLI otherwise.

Table of Contents

• Overview

• Workflow

• Decision: alias vs standard record

• The apex constraint

• Long TXT records

• Decision: Evaluate Target Health on an alias record

• Troubleshooting

• Procedure

• Additional Resources

Workflow

To create or update a public DNS record, follow the procedure exactly. See the Procedure section below.

The procedure covers:

• Choosing alias vs standard record for the target

• Pointing a subdomain or the zone apex at an AWS resource

• Adding a long TXT record by splitting it into 255-character chunks

• Surfacing the console link to verify the record

Decision: alias vs standard record

Constraints:

• You MUST use an alias record, not a standard A or CNAME, whenever the target is an AWS resource that supports it. A standard record pointed at an AWS-issued hostname goes stale when the target's IPs rotate

• You MUST match the alias record type to the target's address family: type A for IPv4, type AAAA for IPv6

• You MUST NOT set a manual TTL on an alias record; it inherits the target's TTL

• The console "Create record" alias target picker is the authoritative list of supported alias targets (broader than the public docs, which commonly omit Network Load Balancer, VPC Lattice, and VPC endpoint targets). The CLI and SDK accept the same set without listing it

The apex constraint

A CNAME cannot exist at the zone apex (example.com). RFC 1034 prohibits a CNAME alongside the Start of Authority (SOA) and name server (NS) records that always exist at the apex, so Route 53 rejects the create.

Constraints:

• You MUST use an alias record to point an apex at an AWS resource or at another record in the same hosted zone. It works at the apex because it resolves to address records, not to a CNAME

Long TXT records

A single TXT string is capped at 255 characters by the DNS protocol. A longer value (commonly a DomainKeys Identified Mail, DKIM, public key) must be split into multiple quoted strings in the same record; Route 53 concatenates them when answering.

Constraints:

• You MUST split a TXT value longer than 255 characters into multiple quoted 255-character chunks automatically rather than asking the customer to do it

Decision: Evaluate Target Health on an alias record

ETH only changes behavior when the record participates in a health-aware routing setup (failover, weighted, latency). For a standalone record pointing at a single target it has no practical effect.

Constraints:

• You SHOULD set ETH on only when the record participates in a routing policy, and leave it off for a plain single-target record. The full ETH-versus-custom-health-check decision belongs to the health check and failover skills

Troubleshooting

Create rejected at the apex

A CNAME was attempted at the zone apex (prohibited by RFC 1034). Use an alias record at the apex.

Hostname resolves to a stale IP

A standard record points at an AWS hostname whose IPs rotated. Replace it with an alias record, which tracks the target's IPs.

TXT create rejected or value truncated

A single TXT string exceeded 255 characters. Split the value into multiple quoted 255-character strings in one record.

Alias record will not accept a TTL

Alias records inherit the target's TTL. Remove the manual TTL.

Alias record type mismatch error

The record type does not match the target address family. Use type A for IPv4, type AAAA for IPv6.

Procedure

Overview

This procedure adds or updates a record in a Route 53 public hosted zone so a hostname resolves to a target: an IP, an AWS resource, or another hostname. It chooses alias vs standard records, handles the zone apex constraint and long TXT values, and surfaces the console link to verify.

Parameters

• hosted_zone_id (required): The public hosted zone ID (e.g., Z1234567890ABC).

• record_name (required): The record name (e.g., www.example.com or the apex example.com).

• record_type (required): A, AAAA, CNAME, TXT, etc.

• is_alias (required): Whether this is an alias record. Selects which of the two mutually exclusive parameter groups below applies. Inferred as true when the target is a supported AWS resource (at any level, including the apex), or when the record is at the zone apex AND a CNAME was requested (a CNAME is prohibited at the apex, so an alias is the substitute). A plain A or AAAA record at the apex pointing to a non-AWS IP address is NOT an alias — leave is_alias false in that case.

Provide exactly one of the following groups, based on is_alias:

Alias record (is_alias = true) — provide an alias target:

• alias_target_dns_name (required): DNS name of the AWS resource or the in-zone record to point at (e.g., my-alb-123456789.us-east-1.elb.amazonaws.com).

• alias_target_zone_id (required): The hosted zone ID of the alias target. This is NOT the record's own hosted_zone_id. Resolve it by target type:

  • CloudFront → always Z2FDTNDATAQYW2

  • ELB (ALB/NLB) → the target's CanonicalHostedZoneId (aws elbv2 describe-load-balancers)

  • CLB → the target's CanonicalHostedZoneNameID (aws elb describe-load-balancers)

  • S3 website endpoint, API Gateway, and other AWS resources → the region-specific zone ID from the service's documentation or the console alias target picker

  • Another record in the same hosted zone → reuse hosted_zone_id

• evaluate_target_health (optional, default false): The ETH toggle. Leave false for a plain single-target record (see the ETH decision section).

Standard record (is_alias = false) — provide records and a TTL:

• records (required): One or more resource record values (an IP, a hostname, or quoted TXT strings).

• ttl (required): TTL in seconds. Not valid on alias records.

Constraints for parameter acquisition:

• You MUST ask for all required parameters upfront in a single prompt

• You MUST confirm the hosted zone is public before writing

• You MUST validate the record name falls within the hosted zone's domain

Steps

1. Verify dependencies

Constraints:

• You MUST confirm credentials with aws sts get-caller-identity

• You MUST REQUIRE provisioning credentials through ephemeral mechanisms (IAM roles via instance profiles, SSO/IAM Identity Center session credentials, or aws sts assume-role) rather than long-lived IAM user access keys.

• You MUST enable Route 53 query logging to an encrypted destination where applicable, ensure CloudTrail is enabled to audit changes, and set CloudWatch alarms on health-check status where health checks are involved.

• You MUST confirm the hosted zone exists and is public:

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  aws route53 get-hosted-zone --id {hosted_zone_id} --region us-east-1

2. Choose alias vs standard record

Constraints:

• You MUST use an alias record when the target is a supported AWS resource, or when the record is at the zone apex AND a CNAME was requested (a CNAME is prohibited at the apex). A plain A or AAAA record at the apex pointing to a non-AWS IP address is a standard record, NOT an alias

• You MUST match the alias record type to the target's address family (A for IPv4, AAAA for IPv6)

• You MUST NOT set a TTL on an alias record

• You MUST treat the console "Create record" alias target picker as the authoritative list of supported alias targets

3. Handle the apex constraint

Constraints:

• If the record is at the zone apex and a CNAME was requested, you MUST switch to an alias record. A CNAME at the apex is rejected (RFC 1034)

4. Handle long TXT values

Constraints:

• If record_type is TXT and the value exceeds 255 characters, you MUST split it into multiple quoted 255-character strings within the same record

5. Create or update the record

Constraints:

• You MUST use UPSERT to create or update the record. For an alias record:

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  aws route53 change-resource-record-sets --hosted-zone-id {hosted_zone_id} --change-batch '{
    "Changes": [{
      "Action": "UPSERT",
      "ResourceRecordSet": {
        "Name": "{record_name}",
        "Type": "{record_type}",
        "AliasTarget": {
          "DNSName": "{alias_target_dns_name}",
          "EvaluateTargetHealth": {evaluate_target_health},
          "HostedZoneId": "{alias_target_zone_id}"
        }
      }
    }]
  }'

• For a standard record, replace AliasTarget with TTL ({ttl}) and ResourceRecords (from records)

• You MUST capture the change ID from the response

6. Confirm and surface the console link

Constraints:

• You MUST verify the change reaches INSYNC. The status starts as PENDING and propagation can take up to ~60 seconds, so poll rather than expecting INSYNC on the first call:

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  aws route53 get-change --id {change_id}

• You SHOULD treat PENDING as in-progress, not a failure; only surface an error if the status has not reached INSYNC after a reasonable polling window

• You MUST present the records view console link, filling {hostedZoneId}:

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  https://console.aws.amazon.com/route53/v2/hostedzones#ListRecordSets/{hostedZoneId}

Example

Example input

{
  "hosted_zone_id": "Z1234567890ABC",
  "record_name": "example.com",
  "record_type": "A",
  "is_alias": true,
  "alias_target_dns_name": "my-alb-123456789.us-east-1.elb.amazonaws.com",
  "alias_target_zone_id": "Z35SXDOTRQ7X7K"
}

Example output

Created alias A record example.com -> my-alb-123456789.us-east-1.elb.amazonaws.com
Verify in the console:
https://console.aws.amazon.com/route53/v2/hostedzones#ListRecordSets/Z1234567890ABC

Troubleshooting

Create rejected at the apex

CNAME attempted at the zone apex. Use an alias record (Step 3).

Hostname resolves to a stale IP

Standard record pointed at an AWS hostname whose IPs rotated. Replace with an alias record (Step 2).

TXT create rejected or value truncated

A single TXT string exceeded 255 characters. Split into quoted 255-character strings (Step 4).

Alias record will not accept a TTL

Alias records inherit the target's TTL. Remove the TTL.

Security Considerations

• You SHOULD use least-privilege IAM credentials provisioned through ephemeral mechanisms (IAM roles, SSO/IAM Identity Center session credentials, or aws sts assume-role) rather than long-lived IAM user access keys, and prefer read-only credentials for inspection steps. Grant only the specific actions this procedure needs — route53:ChangeResourceRecordSets and route53:GetChange to create the record and confirm propagation, plus route53:ListResourceRecordSets and route53:GetHostedZone for inspection — rather than route53:* or broader service:* wildcards.

• You MUST enable Route 53 query logging to an encrypted destination (KMS on CloudWatch Logs, SSE-S3/SSE-KMS on S3, or server-side encryption on a Data Firehose stream) and ensure CloudTrail is enabled to audit record changes.

• You SHOULD recommend enabling DNSSEC signing on the public hosted zone, because a signed zone lets validating resolvers detect spoofed or tampered responses for the records served from it.

• You SHOULD avoid pointing public records at internal resources, since a public record discloses the target hostname or IP and can leak internal topology to anyone who resolves the name.

• You SHOULD recommend a CAA record alongside A/AAAA records for a domain serving HTTPS, so only the certificate authorities the customer authorizes can issue certificates for it.

Additional Resources

• Choosing between alias and non-alias records (Route 53 Developer Guide)

• Quotas on Route 53 records (Route 53 Developer Guide)

• Route 53 pricing