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Junos OS System Log Overview


Junos OS generates system log messages (also called syslog messages) to record events that occur on the device, including the following:

  • Routine operations, such as creation of an Open Shortest Path First (OSPF) protocol adjacency or a user login to the configuration database

  • Failure and error conditions, such as failure to access a configuration file or unexpected closure of a connection to a peer process

  • Emergency or critical conditions, such as router power-down due to excessive temperature

Each system log message identifies the Junos OS process that generated the message and briefly describes the operation or error that occurred.

In Junos OS Release 17.3R1, the syslog-event daemon is able to handle the fxp0 in dedicated management routing instance for for IPv4 addressed remote host. As of Junos OS Release 18.1R1, the syslog-event daemon supports IPv6-based configuration when connecting to a remote host or an archival site and fxp0 is moved to dedicated management instance. In Junos OS Release 18.4R1, the syslog client can send messages through any routing instance you define at appropriate hierarchies. See routing-instance (Syslog).


This topic describes system log messages for Junos OS processes and libraries and not the system logging services on a Physical Interface Card (PIC) such as the Adaptive Services PIC.