unbound-checkconf

Validate Unbound DNS configuration files

TLDR

Check default configuration file

$ unbound-checkconf

Check specific configuration file

$ unbound-checkconf [/etc/unbound/unbound.conf]

Print specific option value

$ unbound-checkconf -o [verbosity]

Check configuration quietly (no output on success)

$ unbound-checkconf -q [/etc/unbound/unbound.conf]

SYNOPSIS

unbound-checkconf [options] [configfile]

unbound-checkconf validates the Unbound DNS resolver configuration file for syntax errors and configuration problems. It checks the specified file or the default configuration location if no file is given.The tool verifies configuration syntax, checks for valid option values, and ensures referenced files (like key files and certificates) exist and are readable. Running this before restarting Unbound prevents service disruption from configuration errors.The -o option extracts specific configuration values, useful for scripting or verifying settings. For disabled options, an empty line is printed.

PARAMETERS

-h

Display help and exit.

-f

Print full pathname with chroot applied. Use with the -o option.

-o option

Print the value of a specific option to stdout.

-q

Quiet mode, suppress output on success.

EXIT STATUS

Returns 0 if the configuration is valid, 1 if errors are found. Error messages indicate the nature and location of problems.

INSTALL

sudo apt install unbound

sudo dnf install unbound

sudo pacman -S unbound

sudo apk add unbound

sudo zypper install unbound

brew install unbound

nix profile install nixpkgs#unbound

CAVEATS

Some errors (like missing auto-generated files) only appear at runtime. Does not validate remote server connectivity. Default configuration path varies by installation.

HISTORY

unbound-checkconf is part of the Unbound DNS resolver developed by NLnet Labs. Unbound was designed as a modern, secure, validating recursive DNS resolver with DNSSEC support, intended as an alternative to BIND for resolver-only deployments.