Domain Name System (DNS) Services

Published April 28, 2025 | Last modified April 25, 2025

Objective

This guide provides instructions on how to set up primary and secondary Domain Name System (DNS) zones in various configurations for specific purposes using F5® Distributed Cloud Services (XC). A DNS zone is a distinct division or subdivision of domain namespace that is managed by an entity such as an organization. A DNS zone allows you to exercise granular control on the components such as name servers which hold the DNS records for the domain namespace represented by the zone.

DNS can be configured in a various was to satisfy different needs or solve different problems. Below are a list of quick-start sections that are commonly used.

Primary DNS This configuration maximizes app performance and improves response times by leveraging F5's geo-distributed anycast network to resolve DNS queries to the closest healthy resource. It also provides a level of built-in DDoS protection.
Dual-Primary DNS Builds in diversity to your environment by standing up two primary DNS services. Teams manage DNS set up in-house, send configurations to the two primary DNS services via API calls, and can leverage either DNS service if one fails.
Secondary DNS Positions the Distributed Cloud DNS service as a secondary DNS service to an existing primary DNS service. This reduces the load on the primary DNS service, provides redundancy in the event of an outage, improves response times, and helps mitigate DDoS attacks.
Secondary DNS (with hidden primary) Positions the Distributed Cloud DNS service as a secondary DNS, but keeps the primary DNS hidden from the internet. This provides enhanced performance via F5's geo-distributed cloud network, enhanced failover, and DDoS protection.

Prerequisites

The following prerequisites apply:

A Distributed Cloud Services Account. If you do not have an account, see Getting Started with Console.
A DNS domain for your web application. Obtain a domain from the Internet domain registrar.
Name servers for managing your DNS records.
To ensure that zone transfers are successful, add the following IP addresses to your firewall or ACL allow list:
- 52.14.213.208
- 3.140.118.214

Configuration

Creating and managing zones involve creating a primary DNS zone and a secondary zone, configuring settings such as records, encryption mechanism, etc.

Create Primary DNS

This procedure will show you how to replace your current DNS server(s) with Distributed Cloud DNS servers. Log into Console and perform the following:

Step 1: Navigate to DNS management and create a primary zone.

Click DNS Management service on the Console home page.

Figure: Navigate to DNS Management

Click Manage > DNS Zone Management in the primary navigation menu located on the left side of the page.
Click Add Zone.

Figure: Add Zone

Enter domain or subdomain name in the Domain Name field in the metadata section.
Optionally, set labels and add a description for your zone.
Select Primary DNS Configuration from the Zone Type drop-down menu in the DNS Zone Configuration section.
Click Edit Configuration under the Primary DNS Configuration field to display the Primary DNS Configuration form.

Figure: DNS Primary Configuration

Step 2: Configure the SOA Parameters.

Select Use Default Parameters from the SOA Record Parameters drop-down menu.
- Optionally, you can customize these parameters by selecting the SOA Record Parameters option and clicking View Configuration. From there you can set the SOA parameters such as refresh interval, retry interval, TTL, etc.

Figure: SOA Custom Configuration

Step 3: Configure resource record set for the default group.

In this step, you will build a list of resource records that will be stored in your zone file.

For each resource record you want to create, click Add Item in the Resource Record Sets section and configure the record in the Resource Record Set configuration form.

Figure: Resource Record Configuration

Enter a value for the Time to live field.
Select a record type from the Record Set drop-down menu.
Enter a name for your record in the Record Name field.
The rest of the form in dependent on the record type you selected. Use the following table for help with each record type.

Record Type	Fields	Notes
A	List of IPv4 Addresses	Enter IPv4 addresses.
AAAA	List of IPv6 Addresses	Enter IPv6 addresses.
ALIAS	Domain	Enter alias domain name.
CAA	Tags and Value	Enter a tag and its value.
CNAME	Domain	Enter domain name.
MX	Domain and Priority	Enter domain and priority in the `MX Record Value` section.
NS	List of Name servers	Enter the FQDN for the name servers.
PTR	List of Name servers	Enter the FQDN for the name servers.
SRV	Priority, Weight, Port, Target	Click `Add Item` in the `SRV Value` section and set the parameters.
TXT	List of Text	Add the TXT record.
DNS Load Balancer	DNS Load Balancer Records	Add the DNS Load Balancer record.
NAPTR	Naming Authority Pointer	Enter regex based domain names used in URIs.
DS	Delegation signer	Enter the signer to identify DNSSEC signing key of a delegated zone.
CDS	Child DS	Enter Child copy of DS record, for transfer to parent.
EUI48	MAC address (EUI-48)	Add uniquely identified MAC address as per the EUI-48 specification.
EUI64	MAC address (EUI-64)	Add uniquely identified MAC address as per the EUI-48 specification.
AFS	AFS record	Enter the AFS record.
DNSKEY	DNS Key	Enter the type, protocol, algorithm, and public key.
CDNSKEY	Child DNS Key	Enter the type, protocol, algorithm, and public key.
LOC	Location information	Enter geographical details such as latitude, longitude, hemispheres, etc.
SSHFP	SSH Key Fingerprint	Enter the fingerprint algorithm, type, and hexadecimal hash result of the ssh key.
TLSA	TLS Certificate Association	Enter the usage, selector, matching type, and association data.
CERT	Public Key Certificate	Enter the type, key tag, algorithm, and certificate.

Use the Add item button available in some record type configurations to add more than one item for that record.

Note: See DNS Load Balancer for instructions on how to configure DNS load balancer for your zone.

Click Apply to save the resource record.

Figure: Resource Record Set

Step 4: Optionally, enable DNSSEC and load balancer management.

In the DNSSEC Mode section, select Enable for the DNSSEC Mode field if you want to use DNS security extensions (DNSSEC) to authenticate DNS response data.

Note: DNSSEC Mode is disabled by default.

Check the Allow HTTP Load Balancer Managed Records. This is only optional for a legacy delegated domain.

Note: Allow HTTP Load Balancer Managed Records is unchecked by default, which might have made sense for a delegated domain. However, Distributed Cloud Services has deprecated the Delegated Domain capability, which means that new domains will need to be setup as a primary DNS zone corresponding to your HTTP Load Balancer (which is what you created in these steps), and you must check the Allow HTTP Load Balancer Managed Records checkbox for the HTTP Load Balancer to work properly.

Step 5: Complete creating the primary zone.

Click Apply in the primary zone configuration form.

Figure: Primary Zone Configuration

Click Save and Exit in the main zone configuration form to complete creating the primary zone.

Step 6: Update your registrar (or parent zones) to replace your current nameservers.

In your domain registrar or parent zone, remove your existing nameservers.
Add two nameservers, ns1.f5clouddns.com and ns2.f5clouddns.com.

Note: This may take a day or two to propagate across the internet.

Validate that your nameserver change has occurred with the following command (be sure to replace <domain> with your domain):
- dig <domain> ns +short
- This should show your two newly added nameservers.

Note: In case you enabled the DNSSEC, the system generates a DS record and displays it in the DNSSEC DS Record column. Click on the displayed value, click Copy DS Record on the displayed window, add the DS record to your parent zone. After the primary zone is created, you can use the dig ds <domain name> command to verify that the DS record digest is displayed in the output. This indicates that DNSSEC is functional.

Create Dual-Primary DNS

**Note: This is an advanced DNS setup. You should have a good understanding of how DNS works prior to using this setup.

The process of creating a dual-primary DNS is almost the same as creating a primary DNS. The only difference is that you will add the Distributed Cloud DNS nameservers to your nameserver list along with your existing primary DNS nameservers.

Once done, you will have two primary DNS servers, both of which are authoritative. This can cause data synchronization problems and conflicts. To avoid these problems, this setup is typically done by organizations that are managing their DNS setups programmatically such that they can update all primary DNS servers at the same time.

There are no steps for creating this setup, because this will typically be done programmatically using the Distributed Cloud API to both create and update the setup.

Create Secondary DNS

Prior to creating secondary zone, ensure that you allow queries from F5 Distributed Cloud IP ranges to your DNS servers.

Log into Console and perform the following:

Step 1: Navigate to zone management and start adding a zone.

Click DNS Management service on the Console home page.

Figure: Navigate to DNS Management

Click Manage > DNS Zone Management in the primary navigation menu located on the left side of the page.
Click Add Zone.
Enter domain or subdomain name in the Domain Name field in the metadata section. Ensure that you enter the same domain name used in primary zone configuration.
Optionally, set labels and add a description.

Step 2: Start configuring secondary zone.

Select Secondary DNS Configuration for the Zone Type field in the DNS Zone Configuration section. Click Configure under the Secondary DNS Configuration field. Do the following in the zone configuration form:

Enter the IP address for your primary zone server in the DNS Primary Server IP field. Use the Add item button to add more than one primary server.
Enter the Transaction Signature (TSIG) key name in the TSIG Key Name field.
Select an algorithm from the TSIG Key Algorithm drop-down menu. Ensure that the key value for the key specified is compatible with the algorithm being selected.

Note: Configuring TSIG key and algorithm is optional. However, it is recommended that you use at least the HMAC-SHA256 algorithm in case you configure TSIG.

Click Configure in the TSIG key value in base 64 format section to encrypt your secret, and do one of the following:
- Paste your secret in the Secret to Blindfold field, and click Apply. The secret type Blindfolded Secret and action Blindfold New Secret are set by default, and your secret is encrypted using Blindfold. You can optionally change the action to Use Existing Blindfolded Secret to add an existing encrypted secret, or use a custom policy instead of a built-in policy using the Policy Type field.
- In case you want to use a clear secret, select Clear Secret for the Secret Type field, and paste your secret in the Secret field. The option text is selected by default, but you can select Base64 and then paste your secret in Base64 format.
- Click Apply

Note: Ensure you obtain the base64 encoded secret if you choose Base64 option for clear secret. You can use echo -n <TSIG KEY> | base64 to convert your secret to Base64 encoded format.

Click Apply.

Figure: Secondary Zone Configuration

Step 3: Complete configuring secondary zone.

Click Save and Exit in the main zone configuration form to create secondary zone.

Step 4: Inspect the secondary zone file.

Select ... > View Zone File in the Actions column for your secondary zone object. This opens the secondary zone file in a read-only window and displays the record name, TTL, record type, and record values.
Click on any record name to open detailed information of that record.

Step 5: Update your registrar (or parent zones) to add XC nameservers.

In your domain registrar or parent zone, add two nameservers, ns1.f5clouddns.com and ns2.f5clouddns.com.

Note: This may take a day or two to propagate across the internet.

Validate that your nameserver change has occurred with the following command (be sure to replace <domain> with your domain):
- dig <domain> ns +short This should show your nameservers including your two newly added nameservers.
- dig @ns1.f5clouddns.com <domain> This should return a header status of NOERROR and a list of your nameservers plus other information. If the header status is REFUSED, then your secondary DNS nameservers are not propagated yet.

Create Secondary DNS (with hidden Primary DNS)

**Note: This is an advanced DNS setup. You should have a good understanding of how DNS works prior to using this setup.

The process of creating a secondary DNS with a hidden primary is almost the same as creating a secondary DNS. The only difference is that you will replace the primary DNS nameservers with the secondary DNS nameservers rather than adding the secondary DNS nameservers to your nameserver list.

Once done, your secondary DNS nameservers will handle all DNS services. If you need to change your DNS setup, you will need to change your primary DNS setup, and then it will update your secondary DNS servers with a DNS change notification followed by a DNS zone transfer.

Step 1: Create Secondary DNS.

Follow steps 1 through 4 in Create Secondary DNS. In other words, follow all but the last step of updating your registrar (that procedure will change slightly).

Step 2: Update your registrar (or parent zones) to replace your current nameservers.

In your domain registrar or parent zone, remove your existing nameservers.
Add two nameservers, ns1.f5clouddns.com and ns2.f5clouddns.com.

Note: This may take a day or two to propagate across the internet.

Validate that your nameserver change has occurred with the following command (be sure to replace <domain> with your domain):
- dig <domain> ns +short
- This should show your two newly added nameservers.

Domain Name System (DNS) Services

Objective

Prerequisites

Configuration

Create Primary DNS

Create Dual-Primary DNS

Create Secondary DNS

Create Secondary DNS (with hidden Primary DNS)

Concepts

References

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