The Listener subsystem is a pluggable interface for inbound unstructured syslog messages. The messages can be received directly from the network devices, via UDP or TCP, or from other third parties, such as brokers, e.g. ZeroMQ, Kafka, etc., depending on the architecture of the network. The default listener is UDP.

From the command line, the Listener can be selected using the --listener option, e.g.:

$ napalm-logs --listener tcp

From the configuration file, the Listener can be specified using the listener option, eventually with several options. The options depend on the nature of the Listener.

Example: listener configuration using the default configuration

listener: tcp

Example: listener configuration using custom options

    buffer_size: 2048
    max_clients: 100


The IP Address / port for the Listener be specified using the address and port: 514 configuration options.

Multiple listeners

New in version 0.4.0.

It is possible to start multiple listeners, each with its separate set of configuration options, however this feature is available only from the configuration file, e.g.:

  - tcp:
      port: 1234
      buffer_size: 2048
      max_clients: 100
  - udp:
      port: 5678

Available listeners and their options