SNMP (Simple Network Management Protocol) is a protocol that is used to monitor network attached devices. SNMP makes it easy to graph out and create baselines and predictions for future usage of your servers. I will show you how to monitor CPU Usage, Memory Usage, Disk Space Usage, UPS Loads, and Network Traffic Loads in this and the next article. If you have any number of servers (And even if you don’t), I recommend using something of this nature to monitor your servers. SNMP have many times let me know about issues (Such as a service hung pegging out a single processor on a Quad-core server).

Vocabulary:

• SNMP Agent – An SNMP agent runs on the target system and responds to SNMP requests from the monitoring system
• OID – Object ID – A string of numbers the monitoring system sends to the target system. It identifies the item or object
• MIB – Managment Information Base – Think of it as a map that displays several objects. You can build a string for an OID using a MIB
• Community Name – Think of this more as a password than anything. Several community names can be defined with different permissions

To Install the SNMP Service on Windows 2003 Server

Click Start->Control Panel->Add/Remove Programs-> Add/Remove Windows Components
Click “Management and Monitoring Tools” and click the “Details” button
Check the box next to “Simple Network Management Protocol”.
Click “Ok” then click “Next”

To Configure the SNMP Service on Windows 2003 Server

Right click on “My Computer” and select “Manage”.
Click the + next to “Services and Applications”.
Select “Services”
Find the “SNMP Service” and right click on it. Select “Properties”
The “Security” tab contains information needed to monitor a server running SNMP

Useful SNMP Tools

Net-SNMP

snmpwalk is a useful tool. For instance, if you run “snmpwalk -v 2c -c Community_Name 192.168.1.1″ snmpwalk will list all OIDs on a machine.

This can be narrowed even further. If we run:

snmpwalk -v 2c -c Community_Name 192.168.1.1 1.3.6.1.2.1.25.3.3.1.2

This will return all OIDs that begin with “1.3.6.1.2.1.25.3.3.1.2″. For instance this returned:

HOST-RESOURCES-MIB::hrProcessorLoad.1 = INTEGER: 0

This means we have an OID that begins with “1.3.6.1.2.1.25.3.3.1.2″ and ends with “.1″. This shows we have a single processor and the current load is 0.