Open SNMP servers are used as reflector in distributed reflected denial of service (DDoS) attack. In this article we show how to protect your SNMP server against abuse.

Step 1

Open the file '/etc/snmp/snmpd.conf':

sudo nano /etc/snmp/snmpd.conf

Step 2

Change the value of 'AgentAddress' to udo:127.0.0.1:161. Any additional AgentAddress should be removed or commented out. Save and close the file afterwards (ctrl + x > y > enter).

Step 3

Use the following command to restart the SNMP server:

service snmpd restart

You can very that your server is no longer vulnerable using the command:

netstat -ln | grep 161 | grep -v 127.0.0.1

This command should return no results.

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