nsd-checkzone(8) | nsd 4.13.0 | nsd-checkzone(8)

# NAME

nsd-checkzone - NSD zone file syntax checker.

# SYNOPSIS

nsd-checkzone [-h] zonename zonefile

# DESCRIPTION

nsd-checkzone reads a DNS zone file and checks it for errors. It prints errors to stderr. On failure it exits with nonzero exit status.

This is used to check files before feeding them to the nsd(8) daemon.

# OPTIONS

-h
  Print usage help information and exit.
zonename
  The name of the zone to check, eg. "example.com".
zonefile
  The file to read, eg. "zones/example.com.zone.signed". Use "-" to read from stdin.
-p
  Print the zone contents to stdout if the zone is ok. This prints the contents as it has been parsed, not literally a copy of the input, but as printed by the formatting routines in NSD, much like the nsd-control command write does.
-i <oldzonefile>
  Create an IXFR from the differences between the old zone file and the new zone file. The argument to the -i option is the old zone file, the other zonefile argument passed is the new zonefile.

  The difference is computed between the two zonefiles by keeping one version of the zone in memory, and another version in a temporary file. The temporary file is located at the zonefile directory. This is also where the result is written, to a file with the zonefile name, ending with '.ixfr'. This is also where NSD reads it when IXFRs are configured for the zone.

  The other existing ixfr files are renamed to become older IXFR contents for the zone, if any such files exist. If the output file already exists with the correct contents, no new file is created. The contents of the header of the output file are checked for that, if it already exists.

-n <ixfr number>
  The number of IXFR versions to store, at most. Default 5. This is the number of files that is created with ixfr contents for the zone. Older stored IXFR versions are deleted when the number is exceeded.
-s <ixfr size>
  The number of bytes of storage to use for IXFRs. Default is 1048576. If an IXFR is bigger it is not created, and if the sum of IXFR storage exceeds it, older IXFRs versions are deleted.

# SEE ALSO

nsd(8), nsd-checkconf(8)

# AUTHORS

NSD was written by NLnet Labs and RIPE NCC joint team. Please see CREDITS file in the distribution for further details.

September 3, 2025 | NLnet Labs