---
type: Monitoring Guide
title: "Door, Contact & Motion Monitoring via SNMP"
description: "Read a dry-contact door or PIR motion sensor's integer state from an SNMP gateway, confirm polarity against the vendor MIB, and alert on after-hours access."
resource: "https://snmp-monitoring.info/monitoring/environmental/door-contact/"
tags: [monitoring]
timestamp: 2026-07-11T00:00:00Z
---

# Door, Contact & Motion Monitoring via SNMP

Read a dry-contact door or PIR motion sensor's integer state from an SNMP gateway, confirm polarity against the vendor MIB, and alert on after-hours access.

## Related concepts

- Up: [SNMP Environmental Monitoring: Temp, Humidity, Leak & Smoke](/monitoring/environmental/index.md)

## Frequently asked questions

### Can SNMP monitor a door sensor?

Yes. A door contact — typically a reed switch — wires into an SNMP environmental gateway as a dry contact, and the gateway reports open/closed as an integer enum in its vendor MIB under 1.3.6.1.4.1. You poll or receive a trap from the gateway and alert on the open state per your rules.

### How do I alert on after-hours access?

Set time-based rules that fire on any door-open or motion event outside defined business hours while staying quiet during the day, and pair the poll with a trap so the alert is immediate. Correlating the event with login activity makes it far more actionable than a bare "door opened."

### What's the difference between a contact and a motion sensor?

A contact sensor (reed switch) detects a specific door opening — binary and per-door. A motion sensor (PIR) detects movement in an area, catching presence even where no monitored door was opened. Contacts give precise per-door events; motion gives broader area coverage. Most setups use both.

### Can SNMP build a physical-access audit trail?

Yes. By logging every door open/close and motion event with timestamps, you get a searchable timeline of physical access that supports compliance reviews and incident forensics — especially when correlated with server-side events like reboots, config changes, or logins.

## Source

Concept generated from https://snmp-monitoring.info/monitoring/environmental/door-contact/ — the SNMP Monitoring vendor-neutral knowledge base. Content is limited to what that page states (no external claims added here).