Learn about the command line arguments and what they mean

to run dnsmonster, one input and at least one output must be defined. The input could be any of devName for live packet capture, pcapFile to read off a pcap file, or dnstapSocket address to listen to. Currently, running dnsmonster with more than one input stream at a time isn’t supported. For output however, it’s supported to have more than one channel. Sometimes, it’s also possible to have multiple instances of the same output (for example Splunk) to provide load balancing and high availability.

Note that in case of specifying multiple output streams, the output data is copied to all. For example, if you put stdoutOutputType=1 and --fileOutputType=1 --fileOutputPath=/dev/stdout, you’ll see each processed output twice in your stdout. One coming from the stdout output type, and the other from the file output type which happens to have the same address (/dev/stdout).

dnsmonster can be configured in 3 different ways. Command line options, Environment variables and a configuration file. You can also use any combination of them at the same time. The precedence order is as follows:

  • Command line options (Case-insensitive)
  • Environment variables (Always upper-case)
  • Configuration file (Case-sensitive, lowercase)
  • Default values (No configuration)

For example, if you have a configuration file that has specified a devName, but you also provide it as a command-line argument, dnsmonster will prioritizes CLI over config file and will ignore that parameter from the ini file.

Command line options

To see the current list of command-line options, run dnsmonster --help or checkout the repository’s

Environment variables

all the flags can also be set via env variables. Keep in mind that the name of each parameter is always all upper case and the prefix for all the variables is “DNSMONSTER.” Example:

$ sudo -E dnsmonster

Configuration file

you can run dnsmonster using the following command to use configuration file:

$ sudo dnsmonster --config=dnsmonster.ini

# Or you can use environment variables to set the configuration file path
$ export DNSMONSTER_CONFIG=dnsmonster.ini
$ sudo -E dnsmonster


Performance considerations when configuring dnsmonster

Last modified August 16, 2022: Update (851fff9)