SNMPAudit

SNMPAudit is a tool for quick discovery of SNMP-enabled devices and obtaining selected information from them. This tool can be used to poll the devices that are present in the specified network address range. SNMP protocol (Simple Network Management Protocol) is used for managing various network devices, such as servers, routers, switches, etc. Having an SNMP-enabled device, it is possible to obtain a great amount of data regarding the status of the device and its functioning.

SNMP protocol uses the community term for indicating the affiliation of an SNMP device with some class according to the functionality of the device and its purpose. An SNMP-enabled device can be configured so that it belongs to several communities. When making a connection to an SNMP device, the console (i.e. Essential NetTools) indicates the community that the request is addressed to. It's important to know the community the device belongs to. If the community is not specified correctly, then the device will simply ignore the request. So, community is also used as an authorization element (the analog of a password), which is necessary to know in order to access an SNMP-enabled device and retrieve data from it.

The commonly used community name is "public". You can add your community to the list of queried communities by clicking the Communities button. Please note that SNMPAudit always checks for the availability of the public community, even if it is not in the community list. Essential NetTools will try each element (i.e. community) from the community list for every address from the specified range. If you are satisfied with just one discovered community per host, then check the Stop checking at the first found community box. In this case, SNMPAudit will stop after the first community is found and will not check the remaining communities from the list. The program will then proceed querying other addresses from the specified range.

Before you start scanning, you should enter the starting and ending IP addresses in the Starting IP and Ending IP fields as shown above. Specify the number of simultaneous connections and connection timeout in the Tasks and Timeout spinboxes. Click on the Start button in order to start scanning. The IP addresses, status of the hosts being queried and other information will appear in the SNMPAudit window during the scan. If a host is not an SNMP-enabled device, you will see a "Can't find remote station" or "Connection rejected" message in the Status column (you can clear the list from failed connections by using the Remove Failed Connections command in the context menu).

If you would like to stop scanning, click on the Stop button. Clicking on the Clear button will empty the list in the main window; however, your current settings such as starting and ending IP addresses, the number of simultaneous connections and connection timeout settings will be preserved.

After discovering a device that belongs to a community from the list, SNMPAudit makes a query for the primary data characterizing the device, and displays the obtained result in the list. You can choose to display the following data columns in the main window of SNMPAudit tool: Device Name, Device Description, Device Location, Device Manufacturer, System ID, Admin Contact Info, and Device Up Time. Right-click on the main window and select Define Columns from the pop-up menu. You will then be able to check the columns that you want displayed and add custom defined data columns.

You cannot modify the settings of Standard Columns or delete them. When adding custom columns you must type in the correct path to SNMP data in the OID column. You can use the drop-down list or look for OID in the respective MIB database. If you would like to delete the column, select it and click on the Delete button.

If you would like to examine a particular SNMP-enabled device from the list of queried devices, double-click on it or select it and click on the Browse button. A SNMP Browser window will open.

SNMP Browser allows you to explore all available data for the given community received from an SNMP device. If the appropriate description exists in the MIB database, you will also be able to read the description of the retrieved data.

Enter the IP address of the device, community, and starting OID in the SNMP browser window. Click Retrieve or just hit Enter. The program will retrieve all underlying data levels beginning with the specified OID. The retrieved data structure will be displayed in the left pane. If you are not sure which OID to start with, choose the starting value from the tree on the left. In this case, the OID field will be automatically filled with the full path to the selected tree element. Usually, all the data belongs to the iso.org or 1.3 branches – please choose OID 1 or 1.3 for retrieving all available data from the selected device.

The actual data received from the device will be displayed in the right pane. Data fields retrieved from the device will be displayed in the left pane and marked with the highlighted icons.

By default, the right pane only displays the data corresponding to the selected tree element (Windows Explorer style). If you'd like to display all data from the subsequent layers, right click on the list and choose Show All Values from the pop-up menu.

You can open as many SNMP browser windows as you wish.

MIB Databases

With the first browser launch, Essential NetTools will load MIB databases from the program folder (by default C:\Program Files\EssNetTools3\SNMP\MIB) and display them as a tree view. MIB stands for Management Information Base and OID stands for Object ID. MIB databases contain the access paths to various data (OID) of the SNMP-enabled devices and the description of the data. You can get the description of an element (if available) by moving the mouse cursor over the corresponding tree element. The description will be displayed in the pop-up window.

MIB databases may be generic or specific for a particular vendor, model, and device class. Essential NetTools is distributed with the basic MIB set, which is sufficient for the majority of devices. You can always obtain specific databases from the public web site http://www.mibdepot.com/. Save them in the application folder (by default C:\Program Files\EssNetTools3\SNMP\MIB) and restart the program. Please note that you are still able retrieve the data without any limitations even if you don't have the right MIB database for the device. MIB databases only provide human-readable descriptions of the retrieved data and its purpose.