How to use the command 'knotc' (with examples)

The ‘knotc’ command is a powerful utility used to control the Knot DNS server, a high-performance authoritative DNS server. By leveraging ‘knotc’, users can efficiently manage DNS zones, manipulate records, and retrieve server configurations. ‘knotc’ provides a command-line interface for facilitating various DNS operations, helping administrators to automate and streamline tasks related to DNS management.

Use case 1: Start editing a zone

Code:

knotc zone-begin zone

Motivation:

When working with DNS records, it’s crucial to ensure that any changes made are precise and deliberate. Starting to edit a zone marks the beginning of modifications to a DNS zone, allowing administrators to prepare the zone for updates.

Explanation:

• knotc: This is the command-line utility for controlling the Knot DNS server.
• zone-begin: This argument signifies the command to start making changes to the specified DNS zone.
• zone: This is the placeholder for the name of the zone you intend to edit.

Example output:

OK

This output indicates that the process of beginning to edit the specified zone has been successfully initiated.

Use case 2: Set an A record

Code:

knotc zone-set zone subdomain 3600 A ip_address

Motivation:

DNS administrators frequently need to add or modify DNS records to ensure that DNS resolutions reflect current infrastructure configurations. Setting an A record associates a domain/subdomain with an IPv4 address, which is crucial for directing web traffic to the correct server.

Explanation:

• knotc: The command-line tool for managing DNS with Knot DNS.
• zone-set: This command is used to modify or add resource records in a DNS zone.
• zone: Represents the DNS zone in which the A record is to be set.
• subdomain: Specifies the subdomain for which the A record is being created.
• 3600: This defines the TTL (Time to Live) for the DNS record in seconds. In this case, 3600 seconds equates to 1 hour.
• A: Indicates the type of DNS record. An ‘A’ record maps a domain to an IPv4 address.
• ip_address: The actual IPv4 address that the subdomain will resolve to.

Example output:

OK

The “OK” output confirms that the A record has been successfully set in the specified zone.

Use case 3: Finish editing the zone

Code:

knotc zone-commit zone

Motivation:

After making changes to a DNS zone, it is imperative to commit these changes to finalize and apply them. This command ensures that all edits are validated and properly recorded, maintaining consistency and accuracy in DNS data.

Explanation:

• knotc: The central utility for controlling Knot DNS server operations.
• zone-commit: This indicates that the editing process for the DNS zone is complete and the changes should be committed.
• zone: The specific DNS zone where changes were made and are now being finalized.

Example output:

OK

This output signifies that the edits made to the zone have been successfully committed and are now active.

Use case 4: Get the current zone data

Code:

knotc zone-read zone

Motivation:

Accessing current DNS zone data is essential for administrators to verify existing configurations, audit record changes, and ensure the accuracy of DNS settings. This command fetches the zone’s data, allowing monitoring and analysis of DNS records.

Explanation:

• knotc: The Knot DNS controlling command-line tool.
• zone-read: This fetches the current data for the specified DNS zone.
• zone: Denotes the name of the DNS zone you wish to query.

Example output:

@ 3600 IN SOA ns1.example.com. hostmaster.example.com. 2023100501 3600 900 1209600 3600
subdomain 3600 IN A 192.0.2.1

The output lists the DNS records, including SOA, A records, etc., present in the specified zone.

Use case 5: Get the current server configuration

Code:

knotc conf-read server

Motivation:

Understanding the current server configuration is vital for diagnostics, performance tuning, and ensuring the server operates within desired parameters. This command provides a view into the server’s settings and parameters.

Explanation:

• knotc: The command-line utility for managing Knot DNS server configurations.
• conf-read: This instructs the tool to read the server’s current configuration settings.
• server: Specifies the target, in this case, the DNS server configuration.

Example output:

server:
  run_dir: "/run/knot"
  user: "knot"
  listen: ["2001:DB8::1@53", "192.0.2.1@53"]

This output displays various configuration settings of the server such as the run directory, the user under which the server operates, and IPs on which the server is listening.

Conclusion:

The ‘knotc’ command is an integral part of managing a Knot DNS server, offering robust functionality for DNS zone handling and server configuration insights. By understanding each of these use cases, administrators can efficiently control and automate their DNS tasks, ensuring seamless DNS management and operations.