This is the blog of Ronald Bartels that wanders on and off the subject of problem management (that is how it started), but it is best described by Ray who says this is Daddy's thoughts! Like the best music is from the Eighties and a wee dram helps in solving most inconveniences.
wtraf - Watcher Traffic SNMP
In the course of his work (administration of active equipment) he faced
the need to quickly obtain online data (preferably with a schedule) of
incoming / outgoing traffic on the network interface via SNMP. In this case, always comes across such equipment that either does not
enter the monitoring system, or requires statistics to be viewed more
often than once a minute (as rrdtool). And in the arsenal, often, only the server console on Windows or Debian.
Download the tool here or checkout a more comprehensive list of tools here.