I just finished configuring MRTG to generate graphs of the CPU usage and the number of active sessions of our Juniper NetScreen Firewalls (via SNMP). Here are the OIDs I find useful:
| OID | Description | Date Type |
| .1.3.6.1.4.1.3224.16.1.1 | Average System CPU utilization in percentage. | integer |
| .1.3.6.1.4.1.3224.16.1.2 | Last one minute CPU utilization in percentage. | integer |
| .1.3.6.1.4.1.3224.16.1.3 | Last five minutes CPU utilization in percentage. | integer |
| .1.3.6.1.4.1.3224.16.1.4 | Last fifteen minutes CPU utilization in percentage. | integer |
| .1.3.6.1.4.1.3224.16.2.1 | Memory allocated. | integer |
| .1.3.6.1.4.1.3224.16.2.2 | Memory left. | integer |
| .1.3.6.1.4.1.3224.16.3.2 | Allocate session number. | integer |
