unboundcheckconf

unboundcheckconf, commonly invoked as unbound-checkconf, is a diagnostic utility distributed with the Unbound DNS resolver. It validates an Unbound configuration file and its included files for syntax errors and basic semantic consistency without starting the resolver.

The tool analyzes the main configuration and any files referenced by include directives, checking syntax rules for options, views, access controls, forwarders, logging, and related settings. It helps detect missing include files, unknown or misspelled options, invalid values, and other configuration issues that would prevent Unbound from starting correctly.

Usage typically involves pointing the command at the main configuration file, usually /etc/unbound/unbound.conf. Depending on the system, there may be additional options to specify alternate directories or provide help via a flag. Users should refer to the installed system’s man page or help output for precise syntax.

Output from unbound-checkconf consists of diagnostic messages describing any problems found, including the file name and line number where the issue occurs. On success, the tool exits with a zero status and may output a confirmation such as “configuration OK” on some versions. On error, it exits with a non-zero status and prints details to aid troubleshooting.

Notes: unbound-checkconf is intended for administrators to validate configuration changes before deployment. While it catches syntax and basic structural issues, it does not perform full runtime validation of dynamic dependencies or operational behavior, and cannot guarantee complete correctness in every scenario. It is the standard first step in preparing an Unbound configuration for production use.