rbldns-data 1 user commands djbwares
rbldns-data compile the database used by rbldns
`rbldns-data`

## Description

`rbldns-data` compiles a database in source form, in the file `data`, into a compiled form, in the file `data.cdb`, that is used by rbldns 1. The compiled database in `data.cdb` is a Bernstein Constant Database file.

`rbldns-data` updates `data.cdb` atomically, building a replacement in `data.cdb.tmp` and atomically renaming that replacement into place when it has completely and successfully built it it and written it to disc. So you can use it safely while rbldns 1 is running.

## Data format

Trailing whitespace is removed from all lines, then all non-empty lines are recognized as follows:

`#comment`

  Comments are ignored.

`:addr:message`

  A record DNS queries are to be answered with addr. TXT record DNS queries are to be answered with message.

  For example:

      :127.0.0.2:See http://rbl.example.com/why/$

`ip`

  The IP address ip is on the RBL blacklist/whitelist.

`ip/n`

  All IP addresses that share the first n bits of ip are on the RBL blacklist/whitelist. This is CIDR notation. n must be at least 8; and all bits of ip past the nth must be 0.

  For example:

      203.0.113.0/24

  means all `203.0.113.*` addresses.

## History

`rbldns-data` was originally part of Daniel J. Bernstein's djbdns toolset in 2000.

## Author

Original code and documentation by Daniel J. Bernstein. Documentation modernizations by Jonathan de Boyne Pollard.