Articles
Active Directory and Group Policy: identity and configuration at scale
How Active Directory stores identity, and how Group Policy outranks local settings.
Operating systems
Directly assigned
Articles
Baseline hardening: the first hour of a new server
The first hour on a new Linux server: patch, restrict access, keep visibility.
Articles
The host firewall: what a server should allow and block by default
Default-deny posture, stateful tracking, and how ufw, firewalld or nftables allow SSH.
Articles
Logs and the journal: what the system recorded and where to find it
Where a Linux host records what happened — and the messages it never writes at all.
Articles
Mounts and filesystems: attaching storage and making it survive a reboot
How Linux attaches a filesystem, and why one wrong /etc/fstab line can stall the boot.
Articles
Packages and updates: installing, upgrading and knowing what changed
How dnf and apt resolve packages, and how to inspect or undo what an update changed.
Articles
Cron and systemd timers: scheduled work and why it fails silently
Two schedulers, one failure mode: cron and systemd timers — and how to prove a job ran.
Articles
SSH and remote administration: keys, sessions and the shape of a connection
Host key, user key and session: what SSH establishes, and the settings that harden it.
Articles
systemd: units, targets and controlling services
Units, not processes: what systemd manages, and how systemctl controls a service.
Articles
Users, groups and permissions in practice: ownership, umask and the effective identity
How a process's effective identity, the mode bits and umask decide file access.
Articles
DNS and DHCP roles on Windows Server
Windows DNS and DHCP roles: installing them, configuring zones and scopes, and verifying.
Articles
Event Viewer, services and updates: keeping a Windows server observable and current
How Windows event logs are read, how services are controlled, and how updates arrive.
Articles
Windows Server roles and features: deciding what the server is for
What Windows Server roles, role services and features are, and how Server Core differs.
Articles
Users, groups and PowerShell: administering Windows Server from the command line
Local users and groups, NTFS permissions with icacls, and PowerShell remoting.
Articles
Firmware, UEFI and the boot path: what runs before the operating system exists
Firmware initialises the platform, chooses what boots and verifies it — all below the OS.
Articles
Filesystems, users, groups and permissions: how a system decides who may touch what
How a system decides who may touch what: mode bits, umask, ACLs and share rules.
Articles
Linux and Windows Server: two operating system models for the same job
Two conventions over the same job: configuration, packages, services, support.
Articles
Processes, services and system management: what is running, and who says so
What is running and who says so: processes, services, their supervisor and its log.