Computer NetworKING & System Administrator

  Introduction Windows Server is widely used in enterprise IT environments to manage users, computers, applications, network services, security, and infrastructure. In this article, we cover important Windows Server interview questions and answers for freshers, experienced System Administrators, L2/L3 engineers, and IT Managers. Section 1: Windows Server Fundamentals 1. What is Windows Server? Windows Server is a Microsoft server operating system designed to provide enterprise services such as Active Directory, DNS, DHCP, file sharing, virtualization, and centralized security management. 2. What is Active Directory? Active Directory Domain Services (AD DS) is a directory service that centrally manages users, computers, groups, authentication, and access permissions within a Windows domain. 3. What is a Domain Controller? A Domain Controller is a server running AD DS that authenticates users and computers and provides directory services to the domain. 4. What is the difference betwe...

  Dell PowerProtect Data Domain System Manager Login Failed While SSH Login Works – Troubleshooting an Expired HTTPS Certificate Introduction While managing a Dell PowerProtect Data Domain appliance, you may encounter a confusing situation where the same sysadmin credentials work successfully through SSH , but the credentials appear to fail when logging in to Data Domain System Manager (DD System Manager) through the web browser. At first, this can look like a password or user-account problem. However, the authentication credentials may be perfectly valid. In this case, the actual root cause was an expired HTTPS certificate used by the Data Domain web interface. This article explains how to troubleshoot this issue systematically and how to safely identify and resolve an expired HTTPS certificate. Problem Statement The issue was: SSH login was successful, but DD System Manager login was not working with the same credentials. The initial assumption could be: Incorrect password Lo...

How to Install VMware PowerCLI on Windows 11 (Offline Method) Introduction VMware PowerCLI is a powerful set of PowerShell modules that allows VMware administrators to automate and manage VMware vSphere environments. Using PowerCLI, you can manage ESXi hosts, vCenter Servers, virtual machines, datastores, networks, snapshots, and much more. This guide explains how to install VMware PowerCLI manually (offline) on a Windows 11 system without downloading it directly from the PowerShell Gallery. Prerequisites Before starting, ensure you have: Windows 11 Windows PowerShell 5.1 or later Administrator privileges VMware PowerCLI offline package (ZIP file) Step 1: Download VMware PowerCLI Download the VMware PowerCLI ZIP package from VMware's official website or another trusted source. After downloading, the file will look similar to: VMware-PowerCLI-<version>.zip Extract the ZIP file using Windows Explorer or a tool such as 7-Zip or WinRAR. Step 2: Extract the ZIP File Right-click th...

Windows Server Interview Questions and Answers – Section 2: Active Directory (25 Questions) Active Directory is one of the most important topics for Windows Server administrators. Whether you are preparing for a Windows Server Administrator, System Administrator, Infrastructure Engineer, or Active Directory Administrator interview, you should understand not only the definitions but also how Active Directory works in a real enterprise environment. In this section, we cover 25 important Active Directory interview questions and answers, from basic concepts such as domains and forests to advanced topics such as FSMO roles, RODC, Active Directory Recycle Bin, and disaster recovery. Q1. What is Active Directory? Answer: Active Directory (AD) is Microsoft’s directory service used to centrally manage users, computers, groups, security policies, and other network resources in a Windows domain environment. The primary Active Directory role used in most organizations is Active Directory Domain Se...

  Appendix B — Top 50 CMD Commands for Windows Server Administrators 1. Network Commands — 1 to 15 # CMD Command Purpose 1 ipconfig Displays basic IP configuration 2 ipconfig /all Displays detailed IP configuration 3 ipconfig /release Releases the DHCP address 4 ipconfig /renew Renews the DHCP address 5 ipconfig /flushdns Clears the DNS resolver cache 6 ipconfig /displaydns Displays cached DNS records 7 ping Tests network connectivity 8 tracert Traces the route to a destination 9 pathping Tests route and packet loss 10 nslookup Queries DNS 11 netstat -ano Displays connections, ports, and PIDs 12 arp -a Displays the ARP cache 13 route print Displays the routing table 14 hostname Displays the computer name 15 getmac Displays MAC addresses 2. Domain and Active Directory Commands — 16 to 25 # CMD Command Purpose 16 whoami Displays the current user 17 whoami /all Displays user SID, groups, and privileges 18 net user Lists local users 19 net user username /domain Displays domain user inf...

Appendix A — Top 100 PowerShell Commands for Windows Server Administrators 1. PowerShell Basics and Help — 1 to 10 # PowerShell Command Purpose 1 Get-Help Displays help for cmdlets 2 Get-Command Lists available commands 3 Get-Member Shows properties and methods of an object 4 Get-Alias Lists PowerShell aliases 5 Get-Module Lists loaded modules 6 Import-Module Imports a PowerShell module 7 Get-ExecutionPolicy Displays the current script execution policy 8 Set-ExecutionPolicy Changes the execution policy 9 Get-History Displays command history 10 Clear-History Clears PowerShell command history 2. System Information — 11 to 20 # PowerShell Command Purpose 11 Get-ComputerInfo Displays detailed computer information 12 Get-CimInstance Win32_OperatingSystem Displays OS information 13 Get-CimInstance Win32_ComputerSystem Displays computer hardware information 14 Get-CimInstance Win32_BIOS Displays BIOS information 15 Get-CimInstance Win32_Processor Displays CPU information 16 Get-HotFix Lists i...

  Commvault One-Touch Recovery Experience and Key Observations Introduction On 09-Jun-2026, I successfully performed a Commvault One-Touch Recovery test. During the recovery process, I observed several important points related to network configuration and disk restoration that may help other administrators avoid common issues. 1. Network Configuration During Recovery The Commvault server in my environment is configured in a Workgroup and is not joined to an Active Directory domain. Due to this configuration, I manually assigned the IP address during the One-Touch Recovery process. Since DNS information is not automatically available in a workgroup environment, the DNS server IP address must also be configured manually. If the server were connected to a domain and using DHCP, the DNS settings would be obtained automatically and hostname resolution would work without manual intervention. Key Point Workgroup Environment: Manual IP and DNS configuration required. Domain Environment wit...

Introduction If your VMware vCenter Server is running out of disk space, especially under /storage/log or /storage/archive , it can impact performance and even stop critical services. In this guide, I’ll walk you through a real-time troubleshooting approach to identify large log files and safely clean them. Step 1: Access vCenter Appliance Shell Login using SSH: login as: administrator@vsphere.local Command> shell Switch to root: sudo -i Step 2: Unlock or Reset Root Account (if needed) /usr/sbin/faillock --user root --reset passwd Step 3: Identify Large Log Files Navigate to log directory: cd /storage/log Find top large files: find . -type f -print0 | xargs -0 du -h | sort -rh | head -n 10 👉 Example output from your system: 1.5G log bundle Multiple 100MB threadmonitor logs Step 4: Remove Unnecessary Large Files Delete large old log bundle: rm vc-localhost-*.tgz Re-check: du -xh -d 1 | sort -rh Step 5: Identify Log Growth Directories find ./ -type d -exec sh -c 'echo -n "{...

  Classic to Modern Azure Site Recovery Migration: Deployment Experience and Key Challenges Migrating from Classic Azure Site Recovery (ASR) to the Modern ASR Appliance architecture introduces several operational differences. During a recent migration, we encountered practical deployment challenges that are worth documenting for others performing similar transitions. OVF Deployment – Unexpected Boot Delay The Modern ASR Appliance was downloaded as an OVF template and deployed into the VMware vCenter environment. Deployment itself was straightforward: • Import OVF • Assign network configuration • Complete virtual hardware mapping However, an unexpected issue arose during the first power-on. The virtual machine took approximately: 30 to 40 minutes to boot This behaviour initially suggested: • Resource bottleneck • OVF corruption • Guest OS issue After reviewing multiple technical forums and blogs, a useful recommendation emerged: Power on the appliance directly from the ESXi host in...