It is very important to continuously monitor the availability of your webservers, NOC servers and core routers and be aware of its health. This plays a major role in the overall infrastructure management of your domain. OpManager enables Network Administrators to monitor their network via various protocols such as ICMP (default), TCP and SNMP.
Monitoring via ICMP - This protocol serves as an effective tool in monitoring the availability of devices (such as routers and ICMP ping serves) in your network. ICMP is the default protocol that is chosen by OpManager during device discovery. The device availability is calculated based on the ping response pattern. This protocol is best suited for larger networks and 'ping' enabled environments. You can choose from either 'Poll using IP Address' or 'Poll using DNS' options from the Monitor Settings page. Poll using DNS is preferred if you have a DHCP environment.
Monitoring via TCP - Here, the availability of the configured device is calculated based on the successful communication between the OpManager server and the TCP port of the monitored device. TCP based availability monitoring is most suitable for ping disabled environments or networks that solely prefer TCP port based monitoring due to security reasons. To enable TCP monitoring, go to the respective device snapshot page, click on Edit device details option and select 'Availability Monitoring Via' as TCP. To perform this action in bulk, select the devices from Inventory and select 'Monitor Availability via TCP' from the Inventory Actions.
Monitoring via SNMP - OpManager also supports SNMP based Availability monitoring. SNMP based availability monitoring can only be configured and used if all the device are SNMP implemented. This requires SNMP credentials to be associated with all the monitored devices. Also, if the credentials expire, the associated device will be notified and marked as Down. SNMP monitoring can be enabled for devices from their respective device snapshot page (under Edit device details option).
Note: The Device Availability is calculated based on the successful SNMP response.
Choosing an availability monitoring protocol is completely based on the network. For example, if you have a ping enabled networks, ICMP protocol wold be the most suitable option. OpManager sends a ping to the monitored devices every 2 minutes (by default) and checks for the response of the devices. This determines the availability of the device in this case. Likewise, the preferred protocol can be chosen by the user, depending on the nature of the network.
Please check the below pages to know more about availability monitoring in OpManager:
Availability monitoring in OpManager
Device availability states and severity
Scalability and hardware recommendations