Windows · Service Management Windows Services A Windows service keeps a piece of software running without anyone signed in to babysit it, and nearly everything that goes wrong with one…
Read More Windows Services
Active Directory · Troubleshooting Stale DNS Records After a Domain Controller Decommission A decommissioned domain controller keeps showing up in DNS — clients still try to reach it, SRV records…
Homelab · Virtualization Proxmox VE Why Proxmox VE has become the default free hypervisor for homelabs and cost-conscious enterprises, and how it stacks up against ESXi, XCP-ng, Hyper-V, and oVirt.…
Active Directory · Troubleshooting DFSR SYSVOL Stuck — Event 4012 and Backlog Not Clearing A growing DFSR backlog or an Event 4012 in the DFS Replication log looks like SYSVOL…
Windows · Task Automation Task Scheduler Task Scheduler runs a program on a schedule or in response to an event instead of someone doing it by hand, and nearly every…
AI Tools · Agent Skills AI Skills: A Beginner’s Guide to Claude and Codex A plain-language walkthrough of what an AI Skill actually is, the exact settings Claude and OpenAI’s…
Windows · Host Firewall Windows Firewall with Advanced Security Windows Firewall with Advanced Security is the host-based packet filter built into every modern Windows client and server, and understanding its…
Active Directory · Troubleshooting Kerberos Clock Skew — KRB_AP_ERR_SKEW KRB_AP_ERR_SKEW means Kerberos has stopped trusting a ticket purely because the clocks on the two machines disagree by more than the…
The trust relationship between this workstation and the primary domain failed - why the machine secure channel breaks and how to fix it without rejoining.
AD replication error 1722 (The RPC Server Is Unavailable): the DNS, port, and firewall causes on the RPC path, diagnosed with repadmin and dcdiag.
No logon servers available to service the logon request - the DNS, DC-reachability, and secure-channel causes, and how to diagnose and fix each.
LDAP bind failures after enforcing LDAP signing and channel binding: find the offending clients via event 2889 and fix insecure LDAP binds.
Fix Kerberos authentication failures from a duplicate SPN (KRB_AP_ERR_MODIFIED): find the duplicate with setspn and remove it safely.
Group Policy not applying? A systematic guide to diagnosing why a GPO will not apply - gpresult, event 1058/1030, SYSVOL and scope - and how to fix it.
Every year someone declares Active Directory dead, and every year most enterprises keep running it. This part closes the series by looking upward: how traditional AD relates to Microsoft Entra ID (formerly Azure AD), what hybrid environments actually look like, what changed, what stayed the same, and where identity is heading.
Active Directory rarely fails loudly. It degrades — quietly, one unnoticed error at a time — until the symptoms surface somewhere far from the cause. This part covers the FSMO roles explained simply, what to check regularly, the early signs that AD is struggling, and the tools that do the checking.
Modern attacks on Active Directory rarely involve breaking anything — they involve logging in with credentials someone left lying around. This part covers privileged accounts, the principle of least privilege, why Domain Admin should almost never be used day to day, and the tier model explained simply.
Domains and forests are boundaries — but businesses do not stay inside boundaries. This part covers what trusts are, how one-way and two-way trusts actually work, and walks through the classic real-world scenario: two companies merging and needing to share resources long before their directories can be combined.
Every administrator knows the call: a user is locked out again, for the fourth time today, and swears they typed the right password. This part covers why lockout policies exist, the surprising causes of lockouts beyond wrong passwords, how Fine-Grained Password Policies work, and how to trace a lockout back to its source.
Why Active Directory cannot function without DNS, how clients use DNS to find Domain Controllers, and why so many AD problems turn out to be DNS problems in disguise.
How Active Directory replication keeps Domain Controllers in sync, what happens when it breaks, and how sites and site links work across offices.
PowerShell · ADOpsKit ADOpsKit – PowerShell Module for Active Directory Operations ADOpsKit is a PowerShell Gallery module that packages commonly needed Active Directory operations into a single install: DC health…
Part 6 of the Active Directory Fundamentals series explains Group Policy, GPO processing order, Computer and User Configuration, LSDOU, default policies, loopback processing, inheritance controls, security filtering, and practical GPO design.
Active Directory · Part 5 Active Directory — Part 5 — Authentication & Kerberos In the earlier parts, we covered what Active Directory is, how domains and forests are structured,…