Devmon: an SNMP device monitor.

What is Devmon?

Devmon is a Perl daemon designed to supplement and enhance the monitoring capabilities of a server running either the BigBrother or Hobbit monitoring software. BigBrother and Hobbit, at present, only support monitoring remote devices via ICMP or TCP port tests.

Devmon takes this a step further, allowing a system administrator to proactively monitor remote devices via SNMP (Simple Network Management Protocol), querying said devices for current status and alarms.

Devmon takes the data that it obtains via SNMP and applies user-defined logic against it and compares the results to user-customizable thresholds. It uses the final data to determine if the remote device is in an abnormal or critical state, and reports accordingly to the BigBrother/Hobbit display server.

Why is Devmon better?

Devmon improves on existing, similar solutions (two examples being the '' perl script, and the non-open source daemon called 'routermon') by providing a solution that is more efficient, fault-tolerant, scalable and maintainable.

Devmon is able to spawn a user-configurable number of child processes to offload the SNMP query workload to, thus creating a psuedo non-blocking SNMP engine. This allows for the rapid query of a large number of remote devices.

For smaller networks, Devmon can be run in a single node configuration, and can be run from the same server as the BigBrother/Hobbit display server. For larger, enterprise networks, Devmon can run in a 'cluster' configuration, with all nodes using a MySQL back-end server (which can also be a cluster, for maximum fault tolerance) for data storage, load balancing, and fault tolerance.

Finally, Devmon supports a flexible, user-customizable template system, which allows an end user with little or no programming knowledge to easily create test logic for any number of different types of devices.

Where can I get Devmon?

You can download Devmon from its page site, here.

What does its output look like?

What its output looks like depends entirely on what monitoring software you are using to display it. Here are some pictures of Devmon's output displayed on a Hobbit server:

Collision test on a Cisco 3548
CPU test on a Cisco 3548
Power test on an APC UPS
Environment test on an APC UPS

Where can I get some help setting it up?

Help is available, on a limited basis, on the Devmon mailing list,, or on the the project forums on the SourceForge project site. Logo