Show Environment Command in Cisco IOS

The Show Environment command can be very helpful to alert you of potential hardware issues. You will need to access this command in global Exec mode.

Here are the options available for the Show Environment command:

show environment [alarms | all | fans | hardware | last | leds | power-supply | table | temperature | voltages]

As you can see, this command has a number of options. You can view the status of your router fans, power supply, system board temperature, and more. Options for this command vary based on the hardware that it is running on.

Let’s look at some examples of the Show Environment command and how it displays information based on different routers and switches.

Output Example from a Router

Cell_Router# show environment

SYS PS1 is present.
Fan status: Normal
Input Voltage status: Normal
DC Output Voltage status: Normal
Type: AC
Thermal status: Normal

SYS PS2 is present.
Fan status: Normal
Input Voltage status: Normal
DC Output Voltage status: Normal
Type: AC
Thermal status: Normal

AUX(-48V) PS1 is absent.

AUX(-48V) PS2 is absent.

Fan 1 Normal
Fan 2 Normal
Fan 3 Normal

Fan Speed is Normal

Alert settings:
Intake temperature warning: Enabled, Threshold: 55
Core temperature warning: Enabled, Threshold: 70 (CPU: 90)

Board Temperature: Normal
Internal-ambient temperature = 35, Normal
CPU temperature = 46, Normal
Intake temperature = 27, Normal
Backplane temperature = 24, Normal

Voltage 1(3300) is Normal, Current voltage = 3300 mV
Voltage 2(5150) is Normal, Current voltage = 5153 mV
Voltage 3(2500) is Normal, Current voltage = 2501 mV
Voltage 4(1200) is Normal, Current voltage = 1203 mV

Nominal frequency


Output Example from a Switch

Cell_Switch# show environment ?
all Show all environment status
fan Show fan status
power Show power supply status
rps Show RPS status
temperature Show temperature status

Cell_Switch# show environment all


As you can see, the functionality of the Show Environment command varies from one hardware platform to another. For example, on the 3845 series, there are additional features, such as the multiple temperature sources and alert thresholds, that can be configured.

Alarms for Environmental Problems

With SNMP in the Cisco IOS, you can be alerted to the environmental conditions that your router is able to monitor. By enabling SNMP on the router, it can send traps to an SNMP management station that alerts you when environmental thresholds are exceeded. To do this, use the envmon SNMP notification type, like this:

snmp-server host public envmon
snmp-server enable traps envmon

With this code, a trap would be sent to your SNMP management station for environmental alerts such as fan failure, temperature thresholds warnings, voltage notifications, or redundant power supply failures.


We hope this helps you to utilize the environment monitoring available on router and switches.

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