# SNMP devices
Plugin: go.d.plugin
Module: snmp
## Overview
This collector monitors any SNMP devices and uses the [gosnmp](https://github.com/gosnmp/gosnmp) package.
It supports:
- all SNMP versions: SNMPv1, SNMPv2c and SNMPv3.
- any number of SNMP devices.
- each SNMP device can be used to collect data for any number of charts.
- each chart may have any number of dimensions.
- each SNMP device may have a different update frequency.
- each SNMP device will accept one or more batches to report values (you can set `max_request_size` per SNMP server, to control the size of batches).
Keep in mind that many SNMP switches and routers are very slow. They may not be able to report values per second.
`go.d.plugin` reports the time it took for the SNMP device to respond when executed in the debug mode.
Also, if many SNMP clients are used on the same SNMP device at the same time, values may be skipped.
This is a problem of the SNMP device, not this collector. In this case, consider reducing the frequency of data collection (increasing `update_every`).
This collector is supported on all platforms.
This collector supports collecting metrics from multiple instances of this integration, including remote instances.
### Default Behavior
#### Auto-Detection
This integration doesn't support auto-detection.
#### Limits
The default configuration for this integration does not impose any limits on data collection.
#### Performance Impact
The default configuration for this integration is not expected to impose a significant performance impact on the system.
## Metrics
The metrics that will be collected are defined in the configuration file.
## Alerts
There are no alerts configured by default for this integration.
## Setup
### Prerequisites
#### Find OIDs
Use `snmpwalk`, like this:
```sh
snmpwalk -t 20 -O fn -v 2c -c public 192.0.2.1
```
- `-t 20` is the timeout in seconds.
- `-O fn` will display full OIDs in numeric format.
- `-v 2c` is the SNMP version.
- `-c public` is the SNMP community.
- `192.0.2.1` is the SNMP device.
### Configuration
#### File
The configuration file name for this integration is `go.d/snmp.conf`.
You can edit the configuration file using the `edit-config` script from the
Netdata [config directory](https://github.com/netdata/netdata/blob/master/docs/netdata-agent/configuration.md#the-netdata-config-directory).
```bash
cd /etc/netdata 2>/dev/null || cd /opt/netdata/etc/netdata
sudo ./edit-config go.d/snmp.conf
```
#### Options
The following options can be defined globally: update_every, autodetection_retry.
Config options
| Name | Description | Default | Required |
|:----|:-----------|:-------|:--------:|
| update_every | Data collection frequency. | 1 | no |
| autodetection_retry | Recheck interval in seconds. Zero means no recheck will be scheduled. | 0 | no |
| hostname | Target ipv4 address. | 127.0.0.1 | yes |
| community | SNMPv1/2 community string. | public | no |
| options.version | SNMP version. Available versions: 1, 2, 3. | 2 | no |
| options.port | Target port. | 161 | no |
| options.retries | Retries to attempt. | 1 | no |
| options.timeout | SNMP request/response timeout. | 10 | no |
| options.max_request_size | Maximum number of OIDs allowed in one one SNMP request. | 60 | no |
| user.name | SNMPv3 user name. | | no |
| user.name | Security level of SNMPv3 messages. | | no |
| user.auth_proto | Security level of SNMPv3 messages. | | no |
| user.name | Authentication protocol for SNMPv3 messages. | | no |
| user.auth_key | Authentication protocol pass phrase. | | no |
| user.priv_proto | Privacy protocol for SNMPv3 messages. | | no |
| user.priv_key | Privacy protocol pass phrase. | | no |
| charts | List of charts. | [] | yes |
| charts.id | Chart ID. Used to uniquely identify the chart. | | yes |
| charts.title | Chart title. | Untitled chart | no |
| charts.units | Chart units. | num | no |
| charts.family | Chart family. | charts.id | no |
| charts.type | Chart type (line, area, stacked). | line | no |
| charts.priority | Chart priority. | 70000 | no |
| charts.multiply_range | Used when you need to define many charts using incremental OIDs. | [] | no |
| charts.dimensions | List of chart dimensions. | [] | yes |
| charts.dimensions.oid | Collected metric OID. | | yes |
| charts.dimensions.name | Dimension name. | | yes |
| charts.dimensions.algorithm | Dimension algorithm (absolute, incremental). | absolute | no |
| charts.dimensions.multiplier | Collected value multiplier, applied to convert it properly to units. | 1 | no |
| charts.dimensions.divisor | Collected value divisor, applied to convert it properly to units. | 1 | no |
##### user.auth_proto
The security of an SNMPv3 message as per RFC 3414 (`user.level`):
| String value | Int value | Description |
|:------------:|:---------:|------------------------------------------|
| none | 1 | no message authentication or encryption |
| authNoPriv | 2 | message authentication and no encryption |
| authPriv | 3 | message authentication and encryption |
##### user.name
The digest algorithm for SNMPv3 messages that require authentication (`user.auth_proto`):
| String value | Int value | Description |
|:------------:|:---------:|-------------------------------------------|
| none | 1 | no message authentication |
| md5 | 2 | MD5 message authentication (HMAC-MD5-96) |
| sha | 3 | SHA message authentication (HMAC-SHA-96) |
| sha224 | 4 | SHA message authentication (HMAC-SHA-224) |
| sha256 | 5 | SHA message authentication (HMAC-SHA-256) |
| sha384 | 6 | SHA message authentication (HMAC-SHA-384) |
| sha512 | 7 | SHA message authentication (HMAC-SHA-512) |
##### user.priv_proto
The encryption algorithm for SNMPv3 messages that require privacy (`user.priv_proto`):
| String value | Int value | Description |
|:------------:|:---------:|-------------------------------------------------------------------------|
| none | 1 | no message encryption |
| des | 2 | ES encryption (CBC-DES) |
| aes | 3 | 128-bit AES encryption (CFB-AES-128) |
| aes192 | 4 | 192-bit AES encryption (CFB-AES-192) with "Blumenthal" key localization |
| aes256 | 5 | 256-bit AES encryption (CFB-AES-256) with "Blumenthal" key localization |
| aes192c | 6 | 192-bit AES encryption (CFB-AES-192) with "Reeder" key localization |
| aes256c | 7 | 256-bit AES encryption (CFB-AES-256) with "Reeder" key localization |
#### Examples
##### SNMPv1/2
In this example:
- the SNMP device is `192.0.2.1`.
- the SNMP version is `2`.
- the SNMP community is `public`.
- we will update the values every 10 seconds.
- we define 2 charts `bandwidth_port1` and `bandwidth_port2`, each having 2 dimensions: `in` and `out`.
> **SNMPv1**: just set `options.version` to 1.
> **Note**: the algorithm chosen is `incremental`, because the collected values show the total number of bytes transferred, which we need to transform into kbps. To chart gauges (e.g. temperature), use `absolute` instead.
Config
```yaml
jobs:
- name: switch
update_every: 10
hostname: 192.0.2.1
community: public
options:
version: 2
charts:
- id: "bandwidth_port1"
title: "Switch Bandwidth for port 1"
units: "kilobits/s"
type: "area"
family: "ports"
dimensions:
- name: "in"
oid: "1.3.6.1.2.1.2.2.1.10.1"
algorithm: "incremental"
multiplier: 8
divisor: 1000
- name: "out"
oid: "1.3.6.1.2.1.2.2.1.16.1"
multiplier: -8
divisor: 1000
- id: "bandwidth_port2"
title: "Switch Bandwidth for port 2"
units: "kilobits/s"
type: "area"
family: "ports"
dimensions:
- name: "in"
oid: "1.3.6.1.2.1.2.2.1.10.2"
algorithm: "incremental"
multiplier: 8
divisor: 1000
- name: "out"
oid: "1.3.6.1.2.1.2.2.1.16.2"
multiplier: -8
divisor: 1000
```
##### SNMPv3
To use SNMPv3:
- use `user` instead of `community`.
- set `options.version` to 3.
The rest of the configuration is the same as in the SNMPv1/2 example.
Config
```yaml
jobs:
- name: switch
update_every: 10
hostname: 192.0.2.1
options:
version: 3
user:
name: username
level: authPriv
auth_proto: sha256
auth_key: auth_protocol_passphrase
priv_proto: aes256
priv_key: priv_protocol_passphrase
```
##### Multiply range
If you need to define many charts using incremental OIDs, you can use the `charts.multiply_range` option.
This is like the SNMPv1/2 example, but the option will multiply the current chart from 1 to 24 inclusive, producing 24 charts in total for the 24 ports of the switch `192.0.2.1`.
Each of the 24 new charts will have its id (1-24) appended at:
- its chart unique `id`, i.e. `bandwidth_port_1` to `bandwidth_port_24`.
- its title, i.e. `Switch Bandwidth for port 1` to `Switch Bandwidth for port 24`.
- its `oid` (for all dimensions), i.e. dimension in will be `1.3.6.1.2.1.2.2.1.10.1` to `1.3.6.1.2.1.2.2.1.10.24`.
- its `priority` will be incremented for each chart so that the charts will appear on the dashboard in this order.
Config
```yaml
jobs:
- name: switch
update_every: 10
hostname: "192.0.2.1"
community: public
options:
version: 2
charts:
- id: "bandwidth_port"
title: "Switch Bandwidth for port"
units: "kilobits/s"
type: "area"
family: "ports"
multiply_range: [1, 24]
dimensions:
- name: "in"
oid: "1.3.6.1.2.1.2.2.1.10"
algorithm: "incremental"
multiplier: 8
divisor: 1000
- name: "out"
oid: "1.3.6.1.2.1.2.2.1.16"
multiplier: -8
divisor: 1000
```
##### Multiple devices with a common configuration
YAML supports [anchors](https://yaml.org/spec/1.2.2/#3222-anchors-and-aliases).
The `&` defines and names an anchor, and the `*` uses it. `<<: *anchor` means, inject the anchor, then extend. We can use anchors to share the common configuration for multiple devices.
The following example:
- adds an `anchor` to the first job.
- injects (copies) the first job configuration to the second and updates `name` and `hostname` parameters.
- injects (copies) the first job configuration to the third and updates `name` and `hostname` parameters.
Config
```yaml
jobs:
- &anchor
name: switch
update_every: 10
hostname: "192.0.2.1"
community: public
options:
version: 2
charts:
- id: "bandwidth_port1"
title: "Switch Bandwidth for port 1"
units: "kilobits/s"
type: "area"
family: "ports"
dimensions:
- name: "in"
oid: "1.3.6.1.2.1.2.2.1.10.1"
algorithm: "incremental"
multiplier: 8
divisor: 1000
- name: "out"
oid: "1.3.6.1.2.1.2.2.1.16.1"
multiplier: -8
divisor: 1000
- <<: *anchor
name: switch2
hostname: "192.0.2.2"
- <<: *anchor
name: switch3
hostname: "192.0.2.3"
```
## Troubleshooting
### Debug Mode
To troubleshoot issues with the `snmp` collector, run the `go.d.plugin` with the debug option enabled. The output
should give you clues as to why the collector isn't working.
- Navigate to the `plugins.d` directory, usually at `/usr/libexec/netdata/plugins.d/`. If that's not the case on
your system, open `netdata.conf` and look for the `plugins` setting under `[directories]`.
```bash
cd /usr/libexec/netdata/plugins.d/
```
- Switch to the `netdata` user.
```bash
sudo -u netdata -s
```
- Run the `go.d.plugin` to debug the collector:
```bash
./go.d.plugin -d -m snmp
```