Centralized UNIX System Monitoring Using SSH and MRTG

There are many system and network monitoring utilities available today. Most of these products rely on the Simple Network Management Protocol (SNMP) to deliver the statistics to a centralized network management station (NMS). I was able to find very few documents that suggest using secure copy (scp) with Public Key authentication from the Secure Shell (SSH) suite as a more secure alternative to SNMP. [1] What documentation I was able to locate did not exactly discuss how to accomplish the task end-to-end. This paper discusses the example of an OpenBSD web server that needs to be monitored by an OpenBSD NMS using the Multi Router Traffic Grapher (MRTG). MRTG is a time-tested and flexible monitoring tool. [2] The procedures in this paper could easily be adapted to gather other system resources and to support other operating systems and other monitoring tools.