Telnet Client is a feature that is included with the Microsoft Operating Systems, but it is not enabled by default.

Telnet client is very much useful for troubleshooting mail flow & for doing port connectivity tests. Let's see the various methods to install Telnet Client in Windows 2012:

Method 1: Install using GUI

1. OpenServer ManagerClick "Manage" 
2. "Add Roles & Features". 
3. Now keep clicking "Next" four times until we get "Select Features" page. 
4. Select "Telnet Client" feature 
5. then click "Next". 
6. Click "Install".

Method 2: Install using Powershell

1. Launch the PowerShell window with elevated permissions (Run as Administrator) 
2. TypeImport-Module servermanager& press enter 
3. TypeAdd-WindowsFeature telnet-client Method 3: Install using Command Prompt 
4. Open command prompt using elevated permissions (Run as Administrator). 
5. Type this command:dism /online /Enable-Feature /FeatureName:TelnetClient 

Once the command completes successfully, telnet client will be installed.