You have a network, and it's your job to keep it running. How do you know it's doing what it should? You could just wait to hear from your users; surely your CIO will let you know when his "internet is broken", but this approach may not have a positive influence on your continued employment. No, you need some network monitoring software. As soon as you are monitoring all the servers, routers, and end user computers on your network, you should consider setting up some SNMP traps on some of your more crucial, core devices so you know exactly what is happening, more or less, when it happens.


First, what is SNMP?


SNMP (Simple Network Monitoring Protocol) is the industry-standard protocol used for communicating with network devices. SNMP-enabled network devices, including routers, switches, and PCs, host SNMP agents that maintain a virtual database of system status and performance information that is tied to specific Object Identifiers (OIDs). This virtual database is referred to as a Management Information Base (MIB), and SNMP-based network monitoring uses MIB OIDs as references to retrieve specific data about a selected, SNMP-enabled, managed devices. "Polling" is the general term we use for this process of data retrieval.


So, what is an SNMP trap?


If you are trying to monitor a large number of devices, where each device may have a large number of its own connected objects, it can become impractical to poll every object of potential interest on every device. SNMP traps and polling work in opposite directions: each SNMP-enabled device you are monitoring can notify you directly if it is having a problem, without solicitation from your network monitoring server.

It's the difference between asking someone, "How are you?" and having that same someone tell you exactly what's bugging them. That's a big difference.


How do I configure an SNMP trap?


Configuration specifics vary from vendor to vender and from device to device. Generally, however, when you are configuring devices to send SNMP traps, confirm that traps are sent to the IP address assigned to the NPM server. To ensure proper configuration, refer to the documentation supplied by the vendor of your devices.

For more information about SNMP traps, see the chapter, "SNMP Traps" in the SolarWinds technical reference, "Introduction to SNMP". For more information about the SolarWinds Trap Viewer, the utility SolarWinds provides with SolarWinds NPM, see the chapter, "Monitoring SNMP Traps", in the SolarWinds Orion Network Performance Monitor Administrator Guide.