Syslog is IOS’ way of telling you something is happening/wrong/breaking/living/winning. It is rather informative and extremely helpful. Best part is you can send it all to a remote server and have it grace the walls of your office/NOC/nerve center!

Below is the format for syslog messages that are generated.


%sys-5-config_1: configured from console by vty0

It is smart to set the system time with NTP so all devices are in sync. This will allow you the ability to accurately determine when the log was generated. Below is the config for sending syslog messages to a server. My server is sitting on the IP address of and I want to trap error syslogs (level 3) and higher.

 sw(config)# logging
 sw(config)# logging trap 3

Logging buffered sends it to the local buffer on the device. Although handy for lab action it is limited to physical memory. Handy for a lab if you are consoling around and want to see what is happening whilst configuring other devices.

Syslog levels for reference.

  • 0  Emergency
  • 1  Alert
  • 2  Critical
  • 3  Error
  • 4  Warning
  • 5  Notice
  • 6  Informative
  • 7  Debugging

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