Our SNMP Scan App searches for SNMP enabled devices. This usually finds printers, home routers and other networked devices. By default, however, Cisco IOS devices won’t be found, and can’t be graphed. This is because Cisco IOS disables SNMP by default.
Here’s to safely enable it.
- Login to your router, switch or access point.
- Enter configuration mode (config term)
- Setup an access list on which network you will allow SNMP requests to come from. In our example, we’ll use the 10.0.1.0/24 network. So we enter
access-list 30 permit 10.0.1.0 0.0.0.255
- Enable SNMP – pick your community name. In our example, we’ll use ‘netfunctional’ as the community name.
snmp-server community netfunctional RO 30
This lets any device which matches Access List 30 talk to our Cisco device using the SNMP community ‘netfunctional’.
- Exit configuration mode – enter
- Save the configuration – enter
Note that these instructions will likely work for Juniper, Foundry Networks and other devices which use Cisco IOS-like syntax for configuration. For more information, see Cisco’s Cisco IOS Configuration – SNMP Chapter.