Monitoring and Troubleshooting
Ping and traceroute are popular troubleshooting tools on any device, and Junos is no exception. There are some advanced options available though (see the command summary below).
Unlike some other vendors, Juniper rely heavily on log files, rather than just writing to screen. Log files are stored in /var/logs. The messages file, in particular, is very useful.
Often there are so many entries in a log file that it’s hard to find what you need. If you want to see just the most recent entries, show the log, and pipe it through the ‘last’ command.
We can monitor log files with the ‘monitor’ command. This shows the newest log entries on the screen as they are added.
Use match with monitor to filter in real-time.
Traceoptions are like debugs on other vendor devices. They are configured per feature that we want to troubleshoot.
Traceoptions write enties to log files, rather than to the screen, but we can use ‘monitor’ to see the entries on the screen as well.
Redirect traceoptions to a syslog server using destination-override syslog host.
If you want to limit who can access a traceoptions file, use world-readable or no-world-readable.
When logging, add explicit-priority to include syslog levels.
If you need assistance, you will need to call JTAC. It will help if you export logs and other relevant information ahead of time.
|ping IP rapid||Operational||A rapid ping (Cisco style)|
|ping IP bypass-routing||Operational||Bypass the routing table for a ping|
|ping IP routing-instance NAME||Operational||Ping using a routing instance|
|traceroute monitor IP||Operational||Continually monitor a path|
|request system storage cleanup||Operational||Free up space|
|show log messages||Operational||Show the messages log|
|show log FILENAME||Operational||Show any log file|
|show system boot-messages||Operational||Show system boot logs|
|monitor start||Operational||Begin monitoring a file in real-time to see changes as they happen|
|monitor list||Operational||See a list of files being monitored|
|monitor stop||Operational||Stop monitoring a file|
|set system syslog host||Configuration||Configure a syslog server|
|set system syslog … source-address||Configuration||Configure a syslog source IP|
|set system syslog console||Configuration||Send syslogs to the console|
|monitor interface||Operational||See interface stats in real-time|
|monitor interface traffic||Operational||Monitor all interfaces at once|
|monitor traffic interface||Operational||A tcpdump style packet capture (traffic to the RE)|
|set … traceoptions file FILENAME flag ITEM||Configuration||Configure traceoptions|
|show chassis alarms||Operational||See any current alarms|
|show chassis environment||Operational||Check temperature, fan status, etc|
|show chassis temperature-thresholds||Operational||Check temperature warning levels|
|show chassis hardware||Operational||See the hardware in your platform|
|show chassis fpc||Operational||Get line card details|
|show chassis cluster||Operational||Get cluster information|
|show chassis routing-engine||Operational||Get RE details|
|show system core-dumps||Operational||Collect core-dump information|
|show system alarms||Operational||Show system alarms|
|show system boot-messages||Operational||Show messages logged during boot|
|show system license||Operational||Show licensing information|
|show system storage||Operational||Show disk usage|
|show system uptime||Operational||See when the system last booted|
|show system process extensive||Operational||Show a full list of processes|
|request system halt||Operational||Power down the system|
|request system power-off||Operational||Power down the system|
|request system software add||Operational||Update Junos|
|request system configuration rescue save||Operational||Update the rescue configuration|
|request system configuration rescue delete||Operational||Delete the rescue configuration|
|request chassis routing-engine master switch||Operational||Change over the active RE|
|request chassis fpc slot NUMBER restart||Operational||Restart a line card|
|rollback rescue||Configuration||Load the rescue configuration|
|request support information | save /var/log/FILENAME||Operational||Collect JTAC support information|
|file archive compress source /var/log/* destination /var/tmp/FILENAME||Operational||Achive support information and logs, ready to be uploaded to JTAC|
|show chassis craft-interface||Operational||Shows the status of the LCD display on MX routers|
|set system syslog user USERNAME||Configuration||Send syslog messages to a users terminal (can use regex, facility, and severity to filter)|
|help syslog||Operational||Get help on syslog messages|
Compressing Troubleshooting Logs from /var/logs to Send to Juniper Networks Technical Support
Displaying Log and Trace Files