Knot DNS server

See the Knot DNS documentation for details on configuring dnstap support. Note that the dnstap support in Knot DNS currently requires protobuf-c 1.0.0 and the latest git snapshot of fstrm.

Unbound DNS server

Add the following lines to unbound.conf:

dnstap:
    dnstap-enable: yes
    dnstap-socket-path: "/var/run/unbound/dnstap.sock"
    dnstap-send-identity: yes
    dnstap-send-version: yes
    dnstap-log-resolver-response-messages: yes
    dnstap-log-client-query-messages: yes

Start Unbound and it will begin sending dnstap payloads to the AF_UNIX socket specified by the dnstap-socket-path variable. Note that Unbound will attempt to connect to this socket path and will periodically attempt to reconnect if a capture tool is not listening for connections. (This allows the capture tool to receive multiple streams of dnstap data over a single socket.)

You also need a capture tool listening on the other side of the socket.

dnstap command-line tool

The following command listens on the given AF_UNIX socket and decodes messages to stdout.

dnstap -u /var/run/unbound/dnstap.sock

The following command listens on the given AF_UNIX socket and saves message payloads to a binary dnstap-format log file.

dnstap -u /tmp/dnstap.sock -w /tmp/test.dnstap

The following command reads a previously saved dnstap-format log file and writes YAML-formatted output to stdout. This format is extremely verbose.

dnstap -y -r test.dnstap

The following command reads a previously saved dnstap-format log file and writes YAML-formatted output to the given output file. This format is extremely verbose.

dnstap -y -r test.dnstap -w test.yaml