Trace options are similar to running a debug in other vendors.

Enable Tracing

When tracing is enabled the results are stored in a trace file in the /var/log/ directory or sent to a remote syslog server.

Remote logging is configured under the system > tracing configuration hierarchy.

The architecture of Junos allow for the enabling of trace options in production without severely impacting a devices operational stability.

Tracing can be enabled at various levels of the configuration hierarchy such as the protocols and interfaces levels.

protocols {
    ospf {
        traceoptions {
            file FILE-NAME [OPTIONS].. ;
            flag FLAG-TYPE ;
            flag FLAG-TYPE detail ;
In order to avoid unnecessary resource utilization disable tracing when debugging is complete.


There are a number of option available when enabling tracing as outline below.

  • file - Name of the trace file
  • size - Maximum size of the file (default: 128KB)
  • files - Number of files to archive (default: 10)
  • no-stamp - Do not place timestamp at start of lines in file (default: Timestamp added)
  • replace - Overwrite existing file (default: Append to file)
  • readable - Allow any user to view file (default: False)
  • no-world-readable - Only user who configured the file can view (default)

View Trace Files

The show log <FILENAME> command is used to view a tracefile.

The monitor start <FILENAME> command starts real-time monitoring of the file.

The monitor stop <FILENAME> command stops real-time monitoring of the file.

The ESC + q key combination starts/stops syslog output to the screen.

Cleanup Trace Files

The clear log <FILENAME> command is used to delete the contents of a trace file.

The file delete <FILENAME> command is used to delete a trace file.


1. Author Unknown (2012) JNCIA-Junos Study Guide-Part 1. Juniper Networks