DNS Records, Hostnames, and Managed Subdomains in UltraDNS

This article explains the difference between DNS records, hostnames, managed domains, and delegated child zones in UltraDNS. 

Use this article when you need to determine whether a name such as www.example.com, app.example.com, or dev.example.com should be managed as a record inside an existing domain or as a separate managed domain.

What This Means

In UltraDNS, names such as www.example.com, app.example.com, and mail.example.com are usually managed as records inside the existing example.com domain.

These names are not separate UltraDNS-managed domains unless they are created as their own domain in UltraDNS or delegated from the parent domain using NS records.

This distinction matters because a record inside a parent domain is managed from the parent domain, while a separately managed child domain or delegated child zone is managed separately.

Simple Rule

Use the following rule when reviewing your UltraDNS configuration:

• If the name appears as an A, AAAA, CNAME, MX, TXT, SRV, or other record inside example.com, it is a record within the example.com domain.
• If the name is created separately in UltraDNS as its own Primary or Secondary domain, or if it is delegated from example.com using NS records, it is managed separately.

Records Inside a Parent Domain

When a domain such as example.com is created in UltraDNS, records can be added under that domain.

For example:

• www.example.com can be an A record inside the example.com domain.
• app.example.com can be a CNAME record inside the example.com domain.
• mail.example.com can be an MX record inside the example.com domain.
• _dmarc.example.com can be a TXT record inside the example.com domain.

These names are hostnames or records within example.com. 

They are not separate UltraDNS-managed domains unless they are also created separately as domains or delegated from the parent domain.

Example: A Record Inside the Parent Domain

If www.example.com is added as an A record under example.com, then www.example.com is managed as a record inside the example.com domain.

You do not need to create www.example.com as a separate domain in UltraDNS just to create an A record for it.

Example: CNAME Record Inside the Parent Domain

If app.example.com is added as a CNAME record under example.com, then app.example.com is managed as a CNAME record inside the example.com domain.

You do not need to create app.example.com as a separate domain in UltraDNS just to create a CNAME record for it.

Example: MX Record Inside the Parent Domain

If mail.example.com is added as an MX record under example.com, then mail.example.com is managed as an MX record inside the example.com domain.

You do not need to create mail.example.com as a separate domain in UltraDNS just to create an MX record for it.

When a Child Name Is Managed Separately

A child name is managed separately when it is created as its own domain in UltraDNS.

For example:

• example.com is created as a domain in UltraDNS.
• dev.example.com is also created as a separate Primary or Secondary domain in UltraDNS.

In this case, dev.example.com is managed separately because it has its own domain entry and its own DNS records.

When a Child Name Is Delegated

A child name can also be delegated from the parent domain using NS records.

For example, the parent domain example.com may contain NS records for dev.example.com.

In that configuration, DNS queries for dev.example.com are referred to the authoritative nameservers listed in those NS records. 

Records for dev.example.com are managed in the delegated child zone, not as ordinary records inside example.com.

Which Term to Use

Use the following terms when working in UltraDNS:

• Use domain when the name exists as a managed domain in UltraDNS.
• Use record when the name exists as an A, AAAA, CNAME, MX, TXT, SRV, NS, or other record inside an existing domain.
• Use hostname as a general term for names such as www.example.com or app.example.com when they are records inside the parent domain.
• Use delegated child zone when the parent domain contains NS records that delegate a child name to another authoritative nameserver set.
• Use separately managed child domain when the child name is created as its own Primary or Secondary domain in UltraDNS.

Common Point of Confusion

A name such as www.example.com may look like it should be managed separately because it appears before example.com.

In UltraDNS, the important question is how the name is configured.

• If the name is configured as a record inside example.com, manage it from the example.com domain.
• If the name is created as its own domain or delegated using NS records, manage it separately.

Summary

In UltraDNS:

• example.com is a managed domain.
• www.example.com can be an A record inside example.com.
• app.example.com can be a CNAME record inside example.com.
• mail.example.com can be an MX record inside example.com.
• dev.example.com is managed separately only if it is created as its own UltraDNS domain or delegated from the parent domain using NS records.

For most entries inside a parent domain, use the terms record or hostname. 

Use separately managed child domain or delegated child zone only when the child name is configured separately from the parent domain.