Wrbldnsd - Rbldnsd for Windows

Wrbldnsd is a Windows anti-spam solution by serving DNSBL zones locally. It is a packaging of Rbldnsd, Rsync and Cygwin. You can use Wrbldnsd to locally mirror DNSBL zone files, thus eliminating latency problems in larger environments and decreasing time used for email filtering significantly.

Rbldnsd is a small and fast DNS daemon which is especially engineered for serving DNSBL zones. It can serve both IP-based and name-based blocklists. All zones are kept in memory for faster performance with a decent memory footprint.  Rsync  uses the Rsync algorithm which provides a very fast method for bringing remote files into sync. It does this by sending just the differences in the files across the link, without requiring that both sets of files are present at one of the ends of the link beforehand. Cygwin is a Linux-like environment for Windows. It consists of a DLL, which emulates substantial Linux API functionality, and a collection of tools.


Wrbldnsd comes as a ZIP file containing an NSIS installer. Simply unzip your downloaded copy and run the installer :

  1. Accept License agreement.
  2. Specify an installation location.
  3. Installation starts. By clicking 'Details' button, you can get more detailed information about installation.


The installer will set up the service Rbldnsd starting the script /rbldnsd.sh, allowing you for customization according to your needs


# Script to start rbldnsd with desired parameters, check man page for other options
# NB! not all of them are applicable as this is a Windows environment

# address - bind to (listen on) this address (required)
export BINDINFO=

# each zone specified using `name:type:file,file...'
export ZONES=localzone:ip4set:local.zone

# working directory
export WORKDIR=/work

#Start rbldnsd
/bin/rbldnsd -n -f -b $BINDINFO -w $WORKDIR $ZONES

 You need to:

  • update the ip address and port to serve the requests (BINDINFO). The default value is non-functional (connections at on port 53)
  • copy dataset files to be used to the /work folder and configure ZONES parameter. 

There are many other options that can be configured via the script file. Check the man page for options.

You can now start the service and monitor the activity via the log file at /var/log folder.

The service is set up in automatic mode and run by the LOCAL SERVICE Account (limited access).

Man page for rbldnsd is available here. More documentation can also be found here.


Wrbldnsd 5.0.0

release date: 
Sun, 09/17/2023

Release announcements