SNMP is ubiquitous due to its simplicity and lightweight protocol based on UDP. Core monitoring in NetCrunch is based on monitoring connectivity and checking responses from Network Services (PING, HTTP, DNS, DHCP, FTP). NetCrunch supports over 70 network protocols and all SNMP versions (v1,v2c, and v3).
The module is part of all NetCrunch products
Reactive monitoring starts with checking the availability and the response time of vital services such as DNS, HTTP, DHCP, RADIUS, and others. NetCrunch does more than checking if the port is open or the connection is established - it verifies the service response to make sure the service is responding correctly.
SNMP protocol is the essential protocol used for monitoring state and performance data of various devices. Even though SNMP is now almost 30 years old, it is still an indispensable part of the monitoring landscape. It is lightweight and straightforward to implement, especially on the agent side, so you can find it in many devices such as switches, printers, UPS, firewall, and others.
This is the most basic monitoring type in NetCrunch. A node state is determined basically by the availability of network services. When a node is in the DOWN state, it's only monitored by a single network service we call
leading service.
NetCrunch automatically discovers services on each machine and starts monitoring them. Each check usually requires sending multiple packets, so that program can calculate packet loss rate and make sure the service is responding, even when it drops some responses.
NetCrunch supports over 70 protocols including a secure version of protocols such as HTTP/S, FTPS, POP3/S, etc.
You can easily duplicate a service definition and make a new one with the different port name. For example, you can change the port and save the HTTP service as "HTTP 8080". You can also create a new protocol check from scratch by defining protocol type, port, data to be sent and response pattern (you can use regexp).
All network service checks are available in the Remote Probe - a lightweight probe that can be installed on a tiny Windows device. You can use it in a similar way as you would Cisco IPSLA, but in this case, it would be to check remote connections and service quality.
Please refer to Distributed Monitoring for more information.
NetCrunch delivers a pre-compiled MIB library containing over 8700 MIBs including Cisco, Nortel, 3Com, Alcatel, and hundreds of the others.
We have grouped modules by vendors, and you can see that some MIB groups like Cisco group contain a massive number of compiled modules (over 1000).
SNMP protocol describes only variables, tables, and basic operations, SNMP tables often refer to other tables to lookup for column values, so it makes reading data not that easy.
NetCrunch SNMP Views can present data in a clean human-readable form. Additionally, views allow changing SNMP values, so they can create a UI for SNMP device.
NetCrunch provides many ready-to-use view definitions for popular devices such as switches, routers or servers. The program also allows creating custom views that can be automatically recognized by the device type and displayed correctly for the device.
Managing node settings is very easy. All you need is to add an element to be monitored to Custom or SNMP Trap or Interface tiles.
The easiest way of managing SNMP settings is using Monitoring Packs.
To monitor SNMP on a particular node, you need to enable SNMP monitor, set its profile and port settings - otherwise it will use the default port.
You can quickly set alerts on numerical values using one of many threshold types available in NetCrunch.
The process is very straightforward, click on Custom and add an <Alert on Performance Trigger>.
Then you will be able to select an SNMP variable as a performance counter. You can find an OID in the MIB library, or you can use the OID if you have one.
You can also monitor text values returned by the SNMP agent. In order to this, you have to select a
<New Event for SNMP Variable Value> alert type.
NetCrunch allows executing Set SNMP Variable action as the alerting action. Additionally, NetCrunch can forward all received traps to another SNMP manager, making device configuration easier.
NetCrunch receives SNMP traps by default, even from nodes that are not in the Atlas. All you need is to configure the device to send it to NetCrunch.
Turning received traps from External Events windows into alerts is easy, the program will create a new node if it is not defined in the Atlas yet. This process simply creates the alert by trap OID. You can also define more complex alerts by filtering certain trap variables.
SNMP v3 protocol uses a different model for notifications than earlier SNMP versions. You need to define a proper authentication profile first, since they have to be decoded using a password and valid encryption settings.
Read more in Receiving SNMPv3 Notifications
As the switches are a vital part of your network, monitoring their performance is unquestionable. Monitoring of switch interfaces allows for bandwidth monitoring.
On the picture above you can see Monitoring Packs added automatically to a switch device.
You can control interface monitoring by the policy. By default, NetCrunch monitors all active interfaces. You can create your own policy and monitor only selected interfaces.
NetCrunch presents traffic on all interfaces.
Furthermore, NetCrunch provides Layer-2 topology mapping with additional module Layer 2 Topology Mapping
NetCrunch allows monitoring the state of Cisco IPSLA operations. You can select operations that were previously defined on a Cisco device. Operations are grouped by the protocol type. You can easily set alerts on status or metrics,
Read more in the documentation Cisco IP SLA Operations
NetCrunch offers two tools to monitors printers. Both of them use SNMP protocols and require Printer MIB v2 to be supported by your printer.
It allows monitoring levels of toner or ink cartridge.
It allows monitoring much more than just checking the supplies level. The sensor supports printer status objects and can observe alarms triggered by the printer.
You can also get free NetCrunch Tools which include SNMP scanner supporting SNMP v3.
Types of SNMP devices include switches, bridges, routers, access servers, computer hosts, servers, UPS-es, printers, IP cameras, and even automation devices that can be controlled thanks to SNMP gateways. These are devices that are part of your SNMP network and relay relevant information via SNMP about the status of various services.
Populating your infrastructure with devices from a single vendor is hard. NetCrunch supports multiple vendors out of the box, including Cisco, HP, Huawei, Juniper, Dell, Alcatel, Arista, and many others.
NetCrunch provides support for over 500 hardware manufacturers - in many cases you do not have to look for MIBs as all are already in the NetCrunch database.
Read more in the documentation chapter Monitoring SNMP Devices