# SNMP Monitoring > The official knowledge base for ostr.io Monitoring (https://ostr.io/service/monitoring): > SNMP protocol fundamentals, the MIB/OID sensor catalog, agent setup and hardening, > HTTP/custom-data checks, tools, comparisons, per-device guides and FAQ. > Every page is fully server-rendered: complete text, tables, FAQ and JSON-LD > (TechArticle + BreadcrumbList + FAQPage) are present in the bare HTML without JavaScript. > > Machine-readable markdown twin of the whole site (OKF v0.1 bundle): > https://snmp-monitoring.com/okf/index.md — start here; https://snmp-monitoring.com/okf.tar.gz — full bundle download. > Each HTML page also links its own concept via . ## Home - [SNMP Monitoring: The Vendor-Neutral Guide](https://snmp-monitoring.com/): Everything about SNMP monitoring: protocol architecture, MIB/OID library, sensors, setup, tools and external monitoring. ## What is SNMP - [What Is SNMP](https://snmp-monitoring.com/what-is-snmp/): SNMP is the Simple Network Management Protocol — a standard way to read health and status from servers, switches and any device over UDP port 161. - [SNMP Architecture](https://snmp-monitoring.com/what-is-snmp/architecture/): SNMP architecture is a client-server design: a manager asks, an agent answers, the managed device runs the agent. How the components talk over UDP. - [SNMP Community Strings](https://snmp-monitoring.com/what-is-snmp/community-strings/): An SNMP community string is a plain-text password carried in every request. Under v1 and v2c it's the whole access story — why 'public' still bites people. - [How SNMP Works: Agents, OIDs & Polling](https://snmp-monitoring.com/what-is-snmp/how-snmp-works/): SNMP works by exchanging small PDUs between manager and agent over UDP — the request names the OIDs, the response carries the values. Get, walk and trap. - [MIB and OID Explained](https://snmp-monitoring.com/what-is-snmp/mib-and-oid/): An OID is the numeric address of one value; a MIB is the dictionary that defines it. Together they give SNMP a single global namespace for machine data. - [SNMP Versions: v1, v2c, v3](https://snmp-monitoring.com/what-is-snmp/snmp-versions/): Three SNMP versions matter — v1, v2c and v3 — and the choice comes down to security on the wire. Community strings versus real authentication and encryption. - [SNMP Traps vs Polling: When to Use Each](https://snmp-monitoring.com/what-is-snmp/traps-vs-polling/): Polling means the manager asks on a schedule; a trap means the agent speaks first when something happens. Opposite directions — and when to reach for each. ## Monitoring concepts - [SNMP Server Monitoring](https://snmp-monitoring.com/monitoring/): Read a server's CPU, memory, disk, uptime and traffic over SNMP with no heavy agent — how server monitoring works and why polling from outside matters. - [Agentless External Monitoring](https://snmp-monitoring.com/monitoring/agentless-external-monitoring/): Agentless monitoring reads what a server already publishes over SNMP; external means reading it off the box — an independent view that survives failures. - [Email & SMS Server Alerts](https://snmp-monitoring.com/monitoring/alerts-email-sms/): Turn SNMP readings into email and SMS alerts that reach a human at 3 a.m. — two channels that fail differently, sent from outside the server they warn about. - [Check Frequency: How Often to Poll](https://snmp-monitoring.com/monitoring/check-frequency/): How often should you poll SNMP? Too rare and outages hide for twenty minutes; too aggressive and you drown the agent. Plus a dual-endpoint trick for both. - [Double Durability: External Server Monitoring](https://snmp-monitoring.com/monitoring/double-durability/): When a server goes down its own tools can't alert you. External, independent monitoring closes the gap. - [Server Health Monitoring](https://snmp-monitoring.com/monitoring/health-monitoring/): Up isn't the same as well. Server health monitoring reads CPU, memory, disk, uptime and processes over SNMP to catch a host sliding toward trouble early. - [HTTP vs SNMP Monitoring](https://snmp-monitoring.com/monitoring/http-vs-snmp-monitoring/): HTTP monitoring tells you a service is reachable; SNMP tells you the machine behind it is healthy. Availability versus health — what each sees and misses. ## Sensors & OID catalog - [What Can SNMP Monitor — Sensor & OID Catalog](https://snmp-monitoring.com/sensors/): What can SNMP monitor? CPU, memory, disks, network throughput, processes, uptime and more — a sensor catalog mapping each metric to its exact OID. - [Complete SNMP Sensor & OID Reference Table](https://snmp-monitoring.com/sensors/all/): A working SNMP OID reference: each server metric paired with the exact object identifier, the MIB that defines it, and whether an external check pulls it. - [Monitor Any Custom OID](https://snmp-monitoring.com/sensors/custom-oid/): If a value lives in a device's MIB tree, you can watch it. Discover any OID, allow it through the agent with one view line, and poll it on a schedule. - [SNMP Environmental Sensors — Temperature, Power & Humidity](https://snmp-monitoring.com/sensors/environmental/): Monitor rack heat, humidity, airflow, voltage, PDUs, UPS units and power supplies over SNMP with vendor MIBs, real OIDs and independent external alerting. - [SNMP Network Interface Monitoring — Bandwidth, Traffic & Errors](https://snmp-monitoring.com/sensors/network/): Poll interface throughput, bandwidth load, packet errors and link state over SNMP using the IF-MIB, with real 64-bit counter OIDs and external alerting. - [SNMP Security & Session Monitoring — SSH Logins & Users](https://snmp-monitoring.com/sensors/security-sessions/): Watch logged-in users and SSH sessions over SNMP with the Host Resources hrSystemNumUsers OID, spot login spikes and alert from outside the network. - [SNMP Server Resource Monitoring — CPU, RAM, Load & Uptime](https://snmp-monitoring.com/sensors/server-resources/): Poll CPU, memory, swap, system load, processes and uptime over SNMP with Host Resources and UCD-SNMP OIDs, plus external reboot and outage alerting. - [SNMP Storage & Disk Monitoring — Capacity, Usage & Inventory](https://snmp-monitoring.com/sensors/storage/): Track disk space, filesystem capacity and storage inventory over SNMP with the Host Resources hrStorage table, real OIDs and external low-space alerting. - [SNMP Fan Speed Monitoring](https://snmp-monitoring.com/sensors/environmental/fan-speed/): A dead fan cooks the parts behind it within minutes. Fan RPM is a leading indicator — read it over SNMP via a vendor MIB or custom OID before heat climbs. - [SNMP Humidity & Airflow Monitoring](https://snmp-monitoring.com/sensors/environmental/humidity-airflow/): The room fails too — damp corrodes, dry air builds static, stalled airflow cooks a rack. Watch humidity and airflow over SNMP from a probe via a vendor MIB. - [SNMP Optical dBm Monitoring](https://snmp-monitoring.com/sensors/environmental/optical-dbm/): A fibre link fades before it fails. Read transmit and receive optical power in dBm off SFP and QSFP modules over SNMP, and catch the slide before it flaps. - [SNMP PDU Monitoring](https://snmp-monitoring.com/sensors/environmental/pdu/): A managed PDU counts every amp it delivers. Poll per-outlet current, bank load and input voltage over SNMP to spot a circuit nearing its breaker limit. - [SNMP Power Supply Monitoring](https://snmp-monitoring.com/sensors/environmental/power-supply/): A redundant PSU can die silently, leaving you one fault from a dark box. Poll each supply's presence, status and draw over SNMP via a vendor or custom OID. - [SNMP RAID Monitoring](https://snmp-monitoring.com/sensors/environmental/raid/): A RAID array hides a dead disk by design. Poll the controller over SNMP for per-disk health, volume state and rebuild progress before a second drive fails. - [SNMP Temperature Monitoring](https://snmp-monitoring.com/sensors/environmental/temperature/): Heat degrades hardware while the dashboard stays green. There's no universal temperature OID — read CPU, intake and aisle heat via a vendor MIB or custom OID. - [SNMP UPS Battery & Runtime Sensors](https://snmp-monitoring.com/sensors/environmental/ups/): Poll a UPS over SNMP for battery status, runtime remaining, charge and load — so you learn about a weak battery on a calm Tuesday, not during the outage. - [SNMP Voltage Monitoring](https://snmp-monitoring.com/sensors/environmental/voltage/): Sagging supply rails cause random reboots and corrupt writes long before anything crashes. Watch voltage over SNMP via a vendor MIB or a custom OID. - [SNMP Bandwidth Monitoring](https://snmp-monitoring.com/sensors/network/bandwidth-load/): Bandwidth monitoring puts throughput in the context of capacity — not how much moved, but how close the link is to full. The OIDs, the math, where to alert. - [SNMP Interface Errors](https://snmp-monitoring.com/sensors/network/interface-errors/): A link can be up and quietly failing. SNMP interface errors and discards expose it — the ifTable columns to read, and why to alert on rate, not totals. - [SNMP Interface Info](https://snmp-monitoring.com/sensors/network/interface-info/): Before graphing traffic you need the interface inventory: names, link state and rated speed from the ifTable, and why a link dropping to down is a top alert. - [SNMP Interface Traffic](https://snmp-monitoring.com/sensors/network/interface-traffic/): Read the octet counters on every network port over SNMP — the 64-bit ifXTable OIDs, why 32-bit counters wrap, and how to turn them into a throughput graph. - [Monitor SSH Logins via SNMP](https://snmp-monitoring.com/sensors/security-sessions/ssh-sessions-logins/): One SNMP counter reports how many user sessions are open right now. On a headless Linux box that's a live login signal — an unexpected jump is a warning. - [SNMP CPU Monitoring](https://snmp-monitoring.com/sensors/server-resources/cpu-utilization/): Watch processor load over SNMP with no agent to install: what the value means on multi-core boxes, the exact OID, and where to set alert thresholds. - [SNMP Process Monitoring](https://snmp-monitoring.com/sensors/server-resources/processes/): Watch what's running on a server over SNMP: catch a fork bomb, a dead daemon or a zombie pile-up from the Host Resources MIB — no shelling in to run ps. - [SNMP Memory (RAM) Monitoring](https://snmp-monitoring.com/sensors/server-resources/ram-memory/): How much RAM is a box using right now, without logging in? The hrStorage OIDs that report physical memory over SNMP, how to query them, and sane thresholds. - [SNMP Swap Monitoring](https://snmp-monitoring.com/sensors/server-resources/swap/): Swap is the pressure gauge for memory — when it fills, RAM already went wrong. The hrStorage OID that reports it, where to set thresholds, and how to read it. - [SNMP System Load Monitoring](https://snmp-monitoring.com/sensors/server-resources/system-load/): Load average is the one number that says whether a server is keeping up. Read the 1-, 5- and 15-minute figures over SNMP, and why it beats CPU percentage. - [SNMP Uptime & Reboot Detection](https://snmp-monitoring.com/sensors/server-resources/uptime-reboot/): SNMP uptime is a counter that only climbs — when it resets, the host rebooted. The exact OID, how to catch silent reboots, and how to spot a reboot loop. - [SNMP Disk Space Monitoring](https://snmp-monitoring.com/sensors/storage/disk-space-usage/): Monitor disk usage over SNMP: the exact OID for space consumed, how to turn allocation units into gigabytes, and how to alert before a volume fills. - [SNMP HDD & SSD Monitoring](https://snmp-monitoring.com/sensors/storage/hdd-ssd/): Standard SNMP tells you how full a disk is, not whether the drive is dying. Which layer answers which question, and where SSD health needs a vendor MIB. - [SNMP Storage Capacity](https://snmp-monitoring.com/sensors/storage/storage-capacity/): Before a disk can be '80% full', something must report what 100% is. The SNMP capacity OID returns total volume size, and tracking it catches silent resizes. - [SNMP Storage Inventory](https://snmp-monitoring.com/sensors/storage/storage-inventory-names/): Every storage number arrives with a bare index. hrStorageDescr maps those indices to real mount points — resolve names before you build any threshold. ## Setup & Configuration - [How to Set Up SNMP Monitoring](https://snmp-monitoring.com/setup/): Set up SNMP monitoring in under 30 minutes: install the daemon, scope access, lock the community, move the port, verify, then watch it from outside. - [Add an SNMP Endpoint in ostr.io](https://snmp-monitoring.com/setup/add-endpoint-ostrio/): Point ostr.io at your SNMP agent in nine clicks and turn a locally-exposed daemon into an externally-monitored one, with real-time alerts when it goes dark. - [Install snmpd on CentOS/RHEL](https://snmp-monitoring.com/setup/centos-rhel/): Install snmpd on CentOS, RHEL, Rocky or AlmaLinux: pull net-snmp with the package manager, drop your snmpd.conf, and start the service. Same daemon as Debian. - [Change the SNMP Port](https://snmp-monitoring.com/setup/custom-port/): Move the SNMP agent off UDP 161 — the first port every scanner checks — in a single snmpd.conf line, plus the firewall rule and how to query the new port. - [Configure /etc/default/snmpd](https://snmp-monitoring.com/setup/default-snmpd-daemon/): The Debian file that decides whether snmpd even starts: SNMPDRUN and the options snmpd launches with — how to edit them and confirm the agent is listening. - [Install snmpd on Ubuntu/Debian](https://snmp-monitoring.com/setup/install-snmpd-ubuntu-debian/): Install snmpd on Ubuntu or Debian the right way: the apt-get command, the /etc/default/snmpd toggle that turns the agent on, and a first walk to prove it. - [SNMP View: Allow/Deny OIDs](https://snmp-monitoring.com/setup/oid-allowlist/): A default agent will read out your whole MIB tree. The snmpd.conf view directive hands out a short allowlist instead — these OIDs and nothing else. - [Secure the Community String](https://snmp-monitoring.com/setup/secure-community-string/): In v2c the community string is the only credential between a stranger and your server — yet it ships as 'public'. Generate a strong one and set it right. - [Configuring snmpd.conf](https://snmp-monitoring.com/setup/snmpd-conf/): A working snmpd.conf, every line explained: com2sec, group, view and access — the four directives that scope a read-only agent to exactly what you monitor. - [SNMP Troubleshooting](https://snmp-monitoring.com/setup/troubleshooting/): SNMP timing out? Walk the chain in order: is the daemon running, the port reachable, the community right, the OID in view? Each fault has a fingerprint. - [Enable SNMP on Windows Server](https://snmp-monitoring.com/setup/windows-server/): SNMP ships as an optional Windows feature, not a package. Turn it on, set a read-only community and permitted hosts, and answer the same OIDs Linux does. ## HTTP & Custom-data monitoring - [HTTP & Uptime Monitoring](https://snmp-monitoring.com/http-monitoring/): HTTP monitoring checks whether the outside world can actually reach your service — status codes, response time and content, watched from off the box. - [Availability Monitoring](https://snmp-monitoring.com/http-monitoring/availability-monitoring/): Availability monitoring answers one question: can people reach your site right now? Response time, status code and uptime, checked from outside your network. - [Custom Data Monitoring (JSON/XML)](https://snmp-monitoring.com/http-monitoring/custom-data-json-xml/): A 200 OK says nothing about the payload. Read a value straight out of a JSON or XML response and alert when queue depth, lag or any number drifts. - [Monitor Nginx Stats](https://snmp-monitoring.com/http-monitoring/nginx-stats/): Tap the Nginx stub_status module for live connection counts — reading, writing, waiting — to spot pile-ups and keep-alive exhaustion before latency climbs. - [Monitor Protected Endpoints](https://snmp-monitoring.com/http-monitoring/protected-endpoints-auth/): Watch URLs behind a login by sending HTTP Basic credentials with every check — how .htpasswd auth works and how to store logins for an external monitor. - [Uncacheable Path Monitoring](https://snmp-monitoring.com/http-monitoring/uncacheable-path/): A cached check can report green while your origin is down. A rotating token forces every probe to a real round-trip, so an outage surfaces immediately. ## Tools & Software - [SNMP Tools & Software](https://snmp-monitoring.com/tools/): The SNMP toolkit explained: command-line utilities, MIB browsers, simulators and external monitoring platforms — what each does and which to reach for. - [Agentless External Monitoring Tools](https://snmp-monitoring.com/tools/agentless-external/): An agentless external tool installs nothing on the server and polls from outside the network — so it keeps working even when the target is on fire. - [SNMP Monitoring Tools Compared](https://snmp-monitoring.com/tools/comparison/): The best SNMP tool depends on the job. Command-line kits, self-hosted open-source stacks and hosted external services, compared on the choices that matter. - [Free vs Paid SNMP Monitoring](https://snmp-monitoring.com/tools/free-vs-paid/): Free SNMP tooling costs no license but spends your time and your monitor's uptime; paid means someone else carries that load. An honest total-cost view. - [MIB Browser: Explore SNMP OIDs & MIBs](https://snmp-monitoring.com/tools/mib-browser/): A MIB browser loads MIB files and lays a device's objects out as a clickable tree — see names, types and descriptions before you query a single OID. - [Net-SNMP (snmpget, snmpwalk)](https://snmp-monitoring.com/tools/net-snmp/): Net-SNMP is the reference toolkit behind snmpget, snmpwalk and snmptranslate. How to install it, fire your first query, and the commands worth memorizing. - [SNMP Simulator (snmpsim)](https://snmp-monitoring.com/tools/snmpsim/): snmpsim stands up a fake SNMP agent that replays values you control — test alerts and build monitoring against a hundred simulated devices on one laptop. ## Security - [SNMP Security](https://snmp-monitoring.com/security/): SNMP ships open: weak community strings, clear-text v2c, an over-broad view, port 161 exposed. Close the doors that leave your agent an easy target. - [SNMP Amplification / DDoS](https://snmp-monitoring.com/security/amplification-ddos/): An exposed SNMP agent on UDP 161 answers a tiny query with a fat reply. Spoof the source and it floods a victim — how the attack works and how to stop it. - [SNMP Security Best Practices](https://snmp-monitoring.com/security/best-practices/): The short SNMP security checklist almost nobody finishes: change the default community, lock the port, show only polled OIDs, authenticate — with real config. - [Hardening SNMP: v3, ACLs & Firewall Rules](https://snmp-monitoring.com/security/hardening/): Turn a wide-open snmpd into one that answers only the right questions, from the right places, with the right credential — a hands-on guide with real config. - [SNMPv1/v2c Security Risks](https://snmp-monitoring.com/security/snmpv1-v2c-risks/): SNMPv1 and v2c authenticate with a single shared word sent unencrypted. Capture the traffic, read the community, and the agent hands over everything. - [SNMPv3 vs v2c Security](https://snmp-monitoring.com/security/v3-vs-v2c/): SNMPv2c authenticates with one clear-text community and encrypts nothing; SNMPv3 adds per-user auth, encryption and access control. What each leaks, compared. - [SNMP Vulnerabilities](https://snmp-monitoring.com/security/vulnerabilities/): Most SNMP vulnerabilities are deployment, not exploits: clear-text credentials, defaults, an exposed agent, an over-broad view. The categories, and the fixes. ## Comparisons - [SNMP vs Alternatives](https://snmp-monitoring.com/comparisons/): Where SNMP wins, where another tool fits, and how they coexist — an honest map for comparing SNMP against Prometheus, Zabbix, Nagios, WMI and more. - [Monitoring Services Compared](https://snmp-monitoring.com/comparisons/monitoring-services/): Uptime pingers, observability suites, self-hosted stacks and lean SNMP checkers, compared on one criterion: can the watcher survive the thing it watches? - [ostr.io vs Alternatives](https://snmp-monitoring.com/comparisons/ostr-io-vs/): An honest look at ostr.io against uptime checkers, observability suites and self-hosted stacks — and the property that decides if you get paged in an outage. - [Self-Hosted vs SaaS Monitoring](https://snmp-monitoring.com/comparisons/self-hosted-vs-saas/): Self-hosted monitoring means control and data ownership; SaaS means zero setup and an outside vantage point. The trade-offs, and why the answer is rarely one. - [SNMP vs GNMI: Legacy vs Streaming Telemetry](https://snmp-monitoring.com/comparisons/snmp-vs-gnmi/): SNMP polls; gNMI streams telemetry over gRPC. The universal default versus the modern challenger — which fits your network, and can they run side by side. - [SNMP vs IPMI: Server Hardware Monitoring](https://snmp-monitoring.com/comparisons/snmp-vs-ipmi/): SNMP polls a running OS; IPMI reaches the hardware directly and keeps working when the OS is gone. In-band versus out-of-band visibility, compared. - [SNMP vs Nagios: Protocol vs Monitoring Tool](https://snmp-monitoring.com/comparisons/snmp-vs-nagios/): SNMP is a protocol that reads a metric; Nagios is an engine that judges it and alerts. Often the real answer to 'SNMP or Nagios' is Nagios using SNMP. - [SNMP vs NetFlow: Device Health vs Traffic](https://snmp-monitoring.com/comparisons/snmp-vs-netflow/): SNMP tells you how much traffic crossed an interface; NetFlow tells you what it was. A meter on the pipe versus an itemized log — and why you need both. - [SNMP vs Prometheus](https://snmp-monitoring.com/comparisons/snmp-vs-prometheus/): SNMP polls infrastructure over UDP 161; Prometheus scrapes app metrics over HTTP. Where each fits and the exporter bridge that connects the two. - [SNMP vs SSH Scripts](https://snmp-monitoring.com/comparisons/snmp-vs-ssh-scripts/): SSH scripts running top and df are flexible but brittle at scale. SNMP polls a structured value instead — where each pulls ahead as your fleet grows. - [SNMP vs Syslog: Metrics vs Logs](https://snmp-monitoring.com/comparisons/snmp-vs-syslog/): SNMP measures — poll a device and get a number. Syslog narrates — a stream of text events. Metrics versus messages, and why you almost always want both. - [SNMP vs WMI: Monitoring Windows Compared](https://snmp-monitoring.com/comparisons/snmp-vs-wmi/): WMI knows a Windows machine intimately but stops at Windows; SNMP knows a little about almost everything. The SNMP vs WMI call comes down to platform reach. - [SNMP vs Zabbix: Protocol vs Platform](https://snmp-monitoring.com/comparisons/snmp-vs-zabbix/): SNMP is a protocol for polling a device; Zabbix is a full monitoring platform. They sit at different layers of the stack — and the answer is often both. ## Devices - [SNMP Device Monitoring](https://snmp-monitoring.com/devices/): One protocol watches your whole fleet over SNMP: servers, switches, routers, firewalls, printers, a UPS. Which OIDs to poll and how to switch it on. - [Monitor Cisco via SNMP](https://snmp-monitoring.com/devices/cisco/): Read per-port bandwidth, link state, uptime and hardware health off Cisco IOS over SNMP — the standard IF-MIB OIDs to poll and how to enable it safely. - [Monitor ESXi/VMware via SNMP](https://snmp-monitoring.com/devices/esxi/): ESXi ships a native SNMP agent, so you read host CPU, memory, datastores and uplinks without installing anything into the VMware kernel. Setup and OIDs. - [Monitor Firewalls via SNMP](https://snmp-monitoring.com/devices/firewall/): Watch a firewall's throughput, link state, session load, CPU and memory over SNMP — pfSense and FortiGate OIDs, and why to poll it from outside the edge. - [Monitor IoT via SNMP](https://snmp-monitoring.com/devices/iot/): SNMP is light enough for constrained IoT hardware, and many embedded devices already speak it. What an agent typically exposes and how to poll it safely. - [Monitor Juniper via SNMP](https://snmp-monitoring.com/devices/juniper/): Enable SNMP on an SRX, EX or MX with a few Junos set statements, then poll the OIDs that matter on Juniper hardware. Views, clients and safe setup. - [Monitor Linux Servers via SNMP](https://snmp-monitoring.com/devices/linux/): One lightweight daemon publishes CPU, memory, disk and uptime through the Host Resources MIB — the OIDs to poll on Linux and a working snmpd.conf. - [Monitor MikroTik via SNMP](https://snmp-monitoring.com/devices/mikrotik/): RouterOS ships an SNMP agent built in — just switch it on. What to enable on MikroTik, which interface and CPU OIDs matter, and the firewall gotcha. - [Monitor NAS via SNMP](https://snmp-monitoring.com/devices/nas/): Poll a Synology or QNAP for free space, CPU, memory and uptime over SNMP, so a filling volume shows as a trend days before it becomes a 2 a.m. incident. - [Monitor Printers via SNMP](https://snmp-monitoring.com/devices/printers/): Poll toner levels, paper trays and error status over SNMP using the standard Printer-MIB (RFC 3805), so you hear about a jam before the queue backs up. - [Monitor a UPS via SNMP — UPS-MIB Setup](https://snmp-monitoring.com/devices/ups/): A UPS with a network card answers the standard UPS-MIB (RFC 1628, 1.3.6.1.2.1.33): read battery status, runtime left and load over SNMP on any brand. - [Monitor Windows via SNMP](https://snmp-monitoring.com/devices/windows/): Poll a Windows Server for CPU, memory, disk and uptime with the same standard OIDs you use on Linux — how to enable the SNMP service and what to watch. ## Guides / Use-cases - [SNMP Monitoring Guides](https://snmp-monitoring.com/guides/): Task-first SNMP guides: catch a filling disk, spot an SSH intruder, build a dashboard, watch a box from outside — each with the exact commands and OIDs. - [Set Up Server Alerts](https://snmp-monitoring.com/guides/alerts/): Set up server alerts that fire on the right condition and reach a human — the two ways SNMP delivers alerts, and why duration beats any single reading. - [Server Monitoring Checklist](https://snmp-monitoring.com/guides/checklist/): A server monitoring checklist in order: from enabling the SNMP agent to alerting from outside the box, with the real OIDs and commands at each step. - [Detect Fraudulent SSH Logins](https://snmp-monitoring.com/guides/detect-fraud-ssh-logins/): Spot an unauthorized SSH login over SNMP without touching a log file: poll the active-session count from outside and alert when it jumps at 3 a.m. - [SNMP + Grafana Dashboards](https://snmp-monitoring.com/guides/grafana/): Grafana can't speak SNMP on its own. The missing piece is a poller writing OIDs into a time-series database — the three-part shape of an SNMP dashboard. - [Set Up Low-Disk-Space Alerts](https://snmp-monitoring.com/guides/low-disk-space-alerts/): Get warned at 80% full, not 100%: the SNMP storage OIDs, the math to turn allocation units into gigabytes, and how to alert from outside the server. - [Monitor Server Resources Externally](https://snmp-monitoring.com/guides/monitor-server-resources-externally/): Poll CPU, memory, storage and uptime over SNMP from a separate machine — and why external checks catch the full crash an on-host agent sleeps through. - [Poll SNMP with Python (pysnmp)](https://snmp-monitoring.com/guides/python-polling/): Pull SNMP metrics into your own Python code with pysnmp — which OIDs to grab, how to fetch them, and where the plain Net-SNMP command line is faster. - [Monitor Web Hosting / VPS](https://snmp-monitoring.com/guides/web-hosting/): Monitor a VPS on two layers: SNMP for the server's vitals and an HTTP check for what visitors see, so a 502 can't hide behind a healthy CPU graph. ## FAQ - [SNMP FAQ](https://snmp-monitoring.com/faq/): Quick answers to the SNMP questions people hit first: which version, which port, what an OID is, and why a walk that worked yesterday times out today. - [SNMP Diagnostics: Test & Debug Agents](https://snmp-monitoring.com/faq/diagnostics/): Test SNMP end to end: prove you can reach the agent, that the community is right, and that the OID returns — the exact commands to isolate each fault. - [SNMP Error Messages](https://snmp-monitoring.com/faq/errors/): Decode common Net-SNMP errors — timeouts, empty walks, 'Unknown Object Identifier' and the noSuch* family — with the cause and the fix for each one. - [Common SNMP Questions](https://snmp-monitoring.com/faq/questions/): The SNMP basics answered concretely: how a manager talks to an agent, why there are three versions, and what those dotted OID numbers actually mean. - [SNMP Standards & RFCs](https://snmp-monitoring.com/faq/standards/): Which SNMP RFC does what: RFC 1157 for v1, RFC 3411 for the v3 framework, SMIv2 for MIBs — a reference table that turns a wall of numbers into a map. ## Glossary - [SNMP Glossary](https://snmp-monitoring.com/glossary/): Plain-language SNMP glossary: agent, manager, OID, MIB, community, trap, PDU, USM, VACM and the three versions, each defined and linked to a deep dive.