To test and validate DNSSEC using the dig command line, you can use the +dnssec option to enable DNSSEC validation and the +sigchase option to automatically follow the chain of trust to the trusted anchor.
DNSSEC (Domain Name System Security Extensions) is a set of security extensions for the DNS protocol that provide authentication and integrity for DNS data. DNSSEC uses digital signatures and public key cryptography to secure DNS data and prevent tampering.
To test and validate DNSSEC using the dig command, you can use the following syntax:
dig +dnssec +sigchase domain.com
This will perform a DNS lookup for the domain.com domain, enable DNSSEC validation, and follow the chain of trust to the trusted anchor to validate the digital signatures.
The dig command will display the DNS record for the domain, along with any DNSSEC-related information, such as the signature algorithm, the signature expiration date, and the key tag.
If DNSSEC validation is successful, the dig command will display the ad flag in the flags field of the output, indicating that the DNS data has been authenticated and is trusted.
If DNSSEC validation is not successful, the dig command will display an error message indicating the reason for the failure.
It is important to note that DNSSEC validation depends on the availability and trustworthiness of the trusted anchor and the chain of trust. If the trusted anchor or the chain of trust is not available or is not trusted, DNSSEC validation will fail.
For more information about the dig command and its options, you can consult the documentation for your specific Unix or Linux system.