Hello,

If someone is wondering how to reboot a Cisco Router without console or vty access to it, you’re lucky. There is a workaround using SNMP commands, if the device has SNMP enabled and with RW permissions.

No need to mention that any access to a Cisco device has to be protected using the proper resources. I mean, if we are going to enable SNMP then we need to protect this access with the community strings and of course with access-list , and of course do not forget to limit this access at the control management plane. We don’t want anyone sending SNMP strings without our authorization, right?

That said, let’s go to with the trick. First of all we need to have a RW community string enabled in the router:

snmp-server community ninjasecret RW

Once we have the router correctly configured we can use SNMP command line tool for your OS. In my case using Windows there is a nice open source project that handles this. You only need to spend a few minutes searching in the Internet.

Now we can do:

snmpset -v2c -c 'ninjasecret' 172.17.172.17 .1.3.6.1.4.9.2.9.9.0 i 2

And that’s all, the router reloads in a silent fashion, I mean, no questions to answer at all.

As a brief explain find below some interesting data.

By the way I highly recommend to move to SNMPv3 as it has better security and encription features.

Hope it helps, see you next time folks!