What is a TXT record?
A TXT record is a type of Domain Name System (DNS) resource record that allows domain owners to store arbitrary text data associated with a particular domain name. TXT records are primarily used for domain verification, providing additional information about a domain, or enabling various other domain-related functionalities.
How TXT records work
When a client, such as a web browser or email server, requests information about a domain, the DNS system returns various types of resource records, including TXT records. These records contain the text data that the domain owner has chosen to associate with that domain.
TXT records are structured as a simple key-value pair, where the key is the domain name and the value is the text data. For example, a TXT record for the domain example.com might look like this:
example.com="This is a sample TXT record."
TXT records can contain any kind of text data, and there is no strict limit on the amount of data that can be stored in a single TXT record. However, most DNS providers recommend keeping the total size of TXT records below 1,024 bytes to ensure compatibility with various systems.
Common uses of TXT records
The most common use cases for TXT records include:
Domain verification
One of the primary uses of TXT records is for domain verification, particularly in the context of email authentication protocols such as Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM). These protocols use TXT records to specify which email servers are authorized to send emails on behalf of a domain, helping to prevent email spoofing and improve email deliverability.
Providing additional domain information
TXT records can also be used to store additional information about a domain, such as the domain owner's contact details, the purpose of the domain, or any other relevant information that the domain owner wants to make publicly available.
Enabling domain-based functionality
Some services and applications may use TXT records to enable specific domain-based functionality, such as website ownership verification for search engines, email forwarding rules, or even custom application-specific data.
Best practices for TXT records
When working with TXT records, it's important to consider the following best practices:
- Carefully manage TXT record content: Ensure that the text data in your TXT records is accurate, up-to-date, and aligned with your intended use case.
- Limit TXT record size: Keep the total size of your TXT records within the recommended 1,024-byte limit to ensure compatibility with various systems.
- Regularly review and update TXT records: Periodically review your TXT records to ensure they are still relevant and serving their intended purpose.
- Coordinate with relevant services: If using TXT records for domain verification or other domain-based functionalities, make sure to coordinate with the relevant service providers to ensure proper implementation and integration.
Example use case: Configuring an SPF TXT record
One common use case for TXT records is to configure an SPF (Sender Policy Framework) record for a domain. SPF is an email authentication protocol that allows domain owners to specify which email servers are authorized to send emails on behalf of their domain.
To configure an SPF TXT record, the domain owner would create a TXT record with the following format:
example.com="v=spf1 include:spf.example.com ~all"
In this example, the TXT record indicates that emails from the example.com domain should only be accepted from the email servers specified in the spf.example.com domain, and any other emails should be treated as suspicious or rejected.