Concepts / Monitoring

Monitoring

SNMP trap

Also called trap, inform, linkDown, snmptrapd, UDP 162

A message an agent sends on its own, to UDP port 162, when something changes, such as a link going down.

Polling finds a problem at the next poll; a trap reports it within seconds. A trap is UDP and unacknowledged, so a lost one is never resent (an inform is the acknowledged kind): stations keep polling as the safety net. A link trap names the card by its ifIndex.

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