How to use SNMPWALK? First of all you have to get Snmpwalk from here. It's better to download the latest stable version.
Once you have downloaded the tool and extracted it from the archive. If you are on a Windows OS it's enough to extract it from the .zip archive. Once you have the snmpwalk.exe file on your computer open the CMD (Start, search cmd and hit Enter). The "black window" will popup. Locate the snmpwalk.exe file and drag it to that black window. Now you have to enter the right command.

Snmpwalk is a great tool that will help you to test SNMP connectivity to one or more devices. It will check if your computer can connect via SNMP. If some ACL or firewall is blocking the snmp access the snmpwalk will fail. The same will happen if the SNMP community string (aka password) is wrong.

Testing Device connectivity using snmpwalk

We have this scenario. You want to check the connectivity to a Cisco router that has IP address 192.168.1.1 - This router is configured with SNMP V2c, and its community string is public

In order to test the connectivity and in order to check if the community string is right you can run the following command:

Snmpwalk Parameters

Here is the meaning of the parameters that we use in our examples:

• -Os print only last symbolic element of OID
• -c set the community string
• -v specifies SNMP version to use

Command example

This is the format of the command that we use in our examples:

Snmpwalk timeout

The timeout message Timeout: No Response from 192.168.1.1 can appear if:

• there is a real timeout - it happens very rarely though:
• there is a firewall blocking SNMP access to the 192.168.1.1 device
• there are specific ACL configured in the devices that block UDP 161 access to the 192.168.1.1 device
• the snmp community string provided is wrong

Snmpwalk works well

In this example we can see that snmpwalk went through. It means that:

• there is SNMP communication with the device 192.168.1.1 on UPD port 161
• there are no ACL or firewallss that are blocking the communication
• the snmp community string provided is right

If you have questions or comments feel free to contact me or leave a comment below

Choose the tool and run the magic!