Supported platforms

Vyatta documentation

Learn how to install, configure, and operate the Vyatta Network Operating System (Vyatta NOS) and Orchestrator, which help drive our virtual networking and physical platforms portfolio.

system syslog

Configures the syslog utility of the system.

set system syslog
delete system syslog
show system syslog

Configuration mode

system {
    syslog {

Use this command to configure the syslog utility of the system.

Using this command, you can set the destinations for log messages from different routing components (facilities) and specify what severity level of message should be reported for each facility.

Log messages generated by the vRouter are associated with one of the following levels of severity.

Table 1. Syslog message severities
Severity Meaning


Emergency. A general system failure or other serious failure has occurred, such that the system is unusable.


Alert. Immediate action is required to prevent the system from becoming unusable; for example, because a network link has failed or the database has become compromised.


Critical. A critical condition exists, such as resource exhaustion—for example, the system is out of memory, CPU processing thresholds are being exceeded, or a hardware failure has occurred.


Error. An error condition has occurred, such as a failed system call. However, the system is still functioning.


Warning. An event has occurred that has the potential to cause an error, such as invalid parameters being passed to a function. This situation should be monitored.


Notice. A normal but significant event has occurred, such as an unexpected event. It is not an error, but could potentially require attention.


Informational. Normal events of interest are being reported as they occur.


Debugging level. Trace-level information is being provided.

The vRouter supports the following standard syslog facilities.

Table 2. Syslog facilities
Facility Description


Authentication and authorization


Nonsystem authorization


Cron daemon


System daemons




Line printer spooler


Mail subsystem


Time stamp


USENET subsystem


Security subsystem


System logging


Application processes


UUCP subsystem


Local facility 0 (unused)


Local facility 1 (unused)


Local facility 2 (unused)


Local facility 3 (unused)


Local facility 4 (unused)


Local facility 5 (user commands)


Local facility 6 (data plane)


Local facility 7 (routing protocols)


All facilities excluding “mark”

Messages are written either to the main log file (the default) or a file that you specify. User-defined log files are written to the /var/log/user directory under the user-specified file name.

The system uses standard UNIX log rotation to prevent the file system from filling with log files. When log messages are written to a file, the system writes up to 250 KB of log messages into the logfile file, where logfile is either the main log file or a name you have assigned to a user-defined file. When the log file reaches its maximum size, the system closes it and compresses it into an archive file. The archive file is named logfile.1.gz.

At this point, the logging utility opens a new log file and begins to write system messages to it. When the new log file is full, the first archive file is renamed logfile.2.gz and the new archive file is named logfile.1.gz.

The system archives log files in this way until a maximum number of log files exist. By default, the maximum number of archive files is 5 (that is, up to logfile.5.gz), where logfile.1.gz always represents the most recent file. After the fifth file, the oldest archive log file is deleted as it is overwritten by the next oldest file.

To change the properties of log file archiving, configure the system syslog archive node with the following parameters.

  • Use the size parameter to specify the maximum size of each archive log file.
  • Use the files parameter to specify the maximum number of archive files to be maintained.

Use the set form of this command to create the syslog configuration.

Use the delete form of this command to remove the syslog configuration.

Use the show form of this command to view the syslog configuration.