SNMP configuration example
This chapter is a guide on configuring SNMP package to establish communication between devices.
SNMP (Simple Network Management Protocol) - is widely used in networking management for networking monitoring. SNMP uses MIB (Management Information Base) to organize management data in the form of variables, which describe the system configuration and status.
Traps are alert messages sent by SNMP agent to SNMP manager.
SNMP agent - Teltonika router. Device which sends Trap messages to the manager.
SNMP manager - device which listens for Trap messages from the agents.
Teltonika routers are able to send SNMP Trap messages to the manager on their own when they experience a problem or a situation described in the rules.
OID code (Object identifier code) - is an address used to identify devices and their status.
OID code is represented by the numbers in the boxes starting from "root".
|1||iso||ISO is the group that established the OID standard|
|3||org||An organization will be specified next|
|6||dod||The US Department of Defense (established the early internet)|
|1||internet||Communication will be via Internet/network|
|4||private||This is a device manufactured by a private entity|
|1||enterprise||The device manufacturer is classified as an enterprise|
|48690||Teltonika||Teltonika enterprise number|
To communicate with Teltonika router the start of the OID code, in this case, will be 126.96.36.199.4.1.48690.
Every configuration or status variable has distinct OID code.
|static||1||Static router information (Router name, Modem Imei, Modem model etc.)|
|gsm||2||Sim card information (Sim State, Operator, Mobile IP etc.)|
|hotspot||3||Hotspot information (Hotspot ip, users etc.)|
|Trap||4||Trap messages (Information sent through trap messages)|
|gps||6||GPS information (Latitude, accuracy etc.)|
|ethernet||7||Information about router ports|
To access variable values, after enterprise number add field number and then specify variable number. For example: .188.8.131.52.4.1.486184.108.40.206 represents router name (486220.127.116.11: Enterprise (48690) - Teltonika, Field (1) - static, Variable (7.0) - routerName). All OID codes can be generated from MIB file, basic OID codes can be found here RUT955 SNMP#SNMP Variables list.
MIB File can be used with MIB browsers for easier access to configuration and status information variables of the device. Download the MIB file and upload/load it in MIB browser. In this example iReasoning MIB browser was used only for testing purpose.
Generating OID code from MIB File
MIB File contains all OID codes. Line containing numbers needed for OID code can be identified by this marking "::=".
All that is left, is to add the numbers together. Example from given MIB File: 18.104.22.168.4.1.48622.214.171.124.
Important note: Do not forget to add .0 at the end of the generated OID code, except to Trap OID codes. Trap OID codes are only used by SNMP agent (router), using them in MIB browser or command line will not give any results.
To configure SNMP, first enable SNMP service, leave or change the port, you can leave everything else as it is.
Press "Download" button to download MIB file.
Testing SNMP with MIB browser
Use MIB browser to test if SNMP works. Make sure to use same port and IP address of the router in MIB browser. To enter port number in MIB browser press "Advanced" button (on the right of IP address field).
To upload/load MIB file press "File" in menu bar (top left side of the window) and press "Load MIBs", make sure to select the MIB file you downloaded from the WebUI. MIB browser lets you walk through all OID codes, or return a distinct variable value. To walk through all OID codes select "walk" in Operation tab (top left of the window). To iterate through OID codes manually, navigate to the desired folder on the left of the MIB browser window and select specific element (Double click). The value of the variable will be printed in the Result Table.
Testing SNMP with console command
We can use snmpget command to get information from router:
$ snmpget -c public -v 2c IP_address:port OID_code
$ snmpget -c public -v 2c 192.168.1.1:161 126.96.36.199.4.1.486188.8.131.52
First enable SNMP Trap, then enter Host/IP, Hots/IP is the SNMP manager, computer to which SNMP agent will send Trap messages. If router is connected to PC via ethernet cable, enter the IP address of the interface the router is connected to. You can use ipconfig command on windows, ifconfig on linux to find IP address of the interface to which router is connected. Next choose port, preferably choose port number higher than 1024 so SNMP manager could establish connection without root/admin rights. If you choose to leave default port 162 make sure to launch SNMP manager with admin/root permissions.
Trap rules describe on what event SNMP agent should send Trap messages. There are certain rules which can be set up using Teltonika WebUI depending on physical configuration of the device.
|Signal strength trap||Minimal mobile signal strength||Teltonika device will send trap message when mobile signal strength falls lower than specified|
|Connection type trap||This trap does not have value||Teltonika device will send trap message when mobile connection establishes or changes|
|Digital input trap||Inactive/Active/Both||Teltonika device will send trap message when Digital input value changes to specified value|
|Digital isolated input trap||Inactive/Active/Both||Teltonika device will send trap message when Digital isolated input value changes to specified value|
|Analog input trap||Higher/Lower/Both + Voltage value||Teltonika device will send trap message when Analog input value fulfills specified requirement|
|Digital output trap||Inactive/Active/Both||Teltonika device will send trap message when Digital output value changes to specified value|
|Digital relay output trap||Inactive/Active/Both||Teltonika device will send trap message when Digital relay output value changes to specified value|
To create new rule chose action and press "Add" button, specify rule values and save.
Example: choose "Connection type trap" action and press "Add" button.
Enable trap rule and press "Save".
New rule should appear in the main Trap window.
Testing Trap with MIB browser
To test trap messages with MIB browser, open Trap receiver and configure the setting. Make sure to use the same port saved in WebUI configuration.
Note: Preferably open MIB browser with root/admin permissions.
To test "Connection type trap" reboot mobile modem. You can reboot modem through Status -> Network window. MIB browser should receive Trap message.
Testing Trap with Linux Terminal
To test Traps with Linux terminal extra configurations and packages are required. All information how to setup Trap listening service and how to test it can be found here Testing Trap With Linux Operating System.