Answer
SNMP trace operations track activity of SNMP agents and record the information in log files.
A sample traceoptions configuration might look like this:
[edit snmp]
user@host# set traceoptions flag all
When the traceoptions flag all statement is included at the [edit snmp] hierarchy level, the following log files are created:
For more information, click: Configuring SNMP on devices running Junos OS