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How to Scan Network Devices

A step by step guide on how to scan your network devices.

In this review, we will explore TNI's network functionality, figure out how to scan a network for devices and why should you do it, how to analyze network equipment, and most importantly, get useful information about all hidden network processes in your organization.

1. Why do you need to scan the network for all devices?

2. What methods can be used to scan a local network using TNI?

3. Scan the network with the IP address scanner.

   3.1. Scan Windows based devices;

   3.2. Scan Linux, Unix OS and macOS devices;

4. How to scan devices on a network using SNMP Network Discovery Software.

 

1. Why do you need to scan the network for all devices?

Before proceeding with the scanning, we first need to figure out why is this procedure is important. Any organization possesses a large amount of technology and without it, a number of work processes would be impossible. In addition to computers based on various OS (Windows, Linux, macOS), servers, laptops, we are surrounded by video surveillance cameras, routers, printers, VOIP, UPS devices, etc., and all of those devices operate over the network. For the correct functioning of each piece of equipment, it is important to correctly perform the initial settings and to maintain the equipment in working order. Quite often happens that the system administrator (the old one quit, the newbie started work) did not track changes in the network and, as a result, does not own information about the IP addresses, does not know when the network was scanned, does not know the tools that are used or were used to check the health of the network, etc. In such cases, scanning network devices is a mandatory procedure to obtain the necessary information.

In addition to the above processes, it is important to know your network architecture. This data is required if you are going to upgrade your hardware, conduct network inventory, connect an additional communication channel (a spare or a faster one). Quite often, a corporate network can become a target for various cyber threats. In this case, timely identification of third-party devices on the network helps prevent tampering and theft of important data.

2. What methods can be used to scan a local network using TNI?

An efficient tool for scanning the network for devices, which is widely used by administrators is Total Network Inventory. It has many built-in useful functions and is highly informative. Basic scanning methods supported by the software:

- scan using WMI – is a standard set of interfaces for accessing devices, applications and parameters of the Windows.

- remote scanning via SMB protocol – to collect the most complete information about the scanned system. The method allows you to remotely run a scan agent with the necessary local privileges to check and remotely access files, load registry data, and collect additional data from system utilities.

- remote scanning via RPC protocol – checking client-server applications based on Windows OS.

- remote scanning using SSH protocol – suitable for Unix systems and macOS.

- remote scanning using SNMP protocol - network printers, managed switches, routers, xDLS modems, IP phones, wireless access points, etc. Listed devices often support this protocol and TNI can let you scan them.

- low-level hardware scanning - TNI downloads and installs a driver to collect low-level hardware data, for example: information from SPD about memory modules, hard disk data, etc.

- manual scan.

3. Scan the network with the IP address scanner.

Let's consider working with an IP address scanner, which is suitable both for Windows and Unix operating systems. Scanning for non-standard network equipment that uses network protocols that do not belong to the type of the above mentioned systems is also available.

It is worth clarifying that the software allows you to work with variety of equipment: network-attached storage devices (NAS), printers, routers, switches, UPS devices, VOIP phones, web servers based on various operating systems. The scanning algorithm is almost the same for all devices (it only differs in the equipment protocol).

Basic scanning algorithm:

  • After starting TNI, you need to select the Scanner tab, specify the range of IP addresses for scanning, workgroup or Active Directory domain.
  • Enter administrator password and start scanning.
  • The software quickly scans the network and provides information in the form of a tree. In the «Viewer and reports» tab, you will see complete information about any of the selected devices.
  • Data can be viewed, reported and exported in different formats.

3.1 Scanning Windows based devices.

There are 3 types of scan for Windows. Let's take a look at the first one - remote scanning via SMB protocol:

  • download the tniwinagent.exe file in the admin$ shared folder on the remote PC.
  • the main TNI module will connect to the Service Manager of the remote computer, install and start the agent as a service.
  • the agent will scan the equipment, save the collected information to a compressed file and stop.
  • the main module imports the resulting file into the repository.
  • the agent service is uninstalled, the executable file is deleted.

Remote scanning via the RPC protocol has no advantages over the previously mentioned options and is recommended for use only when, for one reason or another, the use of the SMB protocol is impossible:

  • TNI's main module connects directly to the target computer's WMI service;
  • via the RPC protocol, connection and collection of information is carried out remotely.

There are certain disadvantages of this method, namely, significant traffic is generated and the scan speed may drop because of a slow connection.

3.2. Scan Linux, Unix OS and macOS devices.

Scanning computers running macOS (64 bit only), Linux, FreeBSD and ESX/ESXi is carried out using an executable file, which is downloaded to a remote PC via SSH and SCP/SFTP and collects information. There are certain things to consider before starting a scan:

  • the remote computer must be running an SSH-2 server (TCP on port 22, or set the "Special SSH port" in the application settings) with SFTP or SCP support, and the firewall must allow access to it;
  • the user on whose behalf the scan is performed is allowed access to the SSH server (server option AllowUsers). If scanning is performed as a root user, then the PermitRootLogin - yes option must also be set for it;
  • user must have administrator rights (for Linux OS, if he is not root - must be in the sudoers list).

Remote scanning using SSH protocol.

  • TNI connects to a remote computer using the specified protocol - a temporary folder is created in the home folder of the user on whose behalf the scan is performed, to which the scan agent is transferred via SFTP or SCP.
  • the scan agent starts and upon completion creates a file with the information collected about the network.
  • the file with information is transferred via SFTP or SCP back to TNI, which, in turn, adds it to the open storage.
  • the temporary folder with the agent and the created file is deleted.

4. How to scan devices on a network using SNMP Network Discovery Software.

To carry out an inventory in this way, the user does not have to use dozens of commands, find out whether a certain technique is using a dynamic or static IP. SNMP scanner is easy to set up and run, but despite this, it will collect detailed information about each router, switch, network printer in just one pass.

The algorithm for starting and scanning is the same as for the above function, except that you need to select the “SNMP” function.

In conclusion.

To scan devices on the network, you should use trusted software. You will forget about manually entering commands into the console, you can conduct a detailed scan of any network equipment on the network under the control of a variety of operating systems. Download Total Network Inventory and get all the information you need in just a couple of clicks at any time convenient for you.

 

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