IT cheat sheets
Field-ready commands, checks and interpretation notes for day-to-day IT operations.
Active Directory — Essential Controls
Active Directory operations reference covering identity, replication, FSMO, DNS, Kerberos, GPO, time, secure channel and health checks.
Backup & VSS — Cheat sheet
Windows backup and VSS reference covering 3-2-1-1-0, RPO/RTO, writers, providers, shadow storage, events and restore validation.
DNS — memo form
DNS reference for records, resolvers, authoritative servers, delegation, caching and Active Directory zones.
FortiGate — diagnostic memo
FortiGate CLI reference for system state, interfaces, ARP, routing, sessions, policy/NAT, SD-WAN, IPsec and debug flow.
HTTP — essential codes and headers
HTTP reference for methods, status codes, redirects, headers, caching, CORS, security and TLS/web troubleshooting.
Linux — Essential commands
Linux field reference for system, processes, systemd, logs, storage, networking, DNS, firewall, accounts and SSH.
Microsoft 365 — memo administration
Microsoft 365 administration reference for Entra identity, Exchange Online, SharePoint/OneDrive, Teams, Intune, PowerShell, mail traces and security checks.
Network ports — memo form
Reference of common ports, protocols and troubleshooting context; a known port never means it should be exposed to the Internet.
PowerShell — Essential commands
Field reference for PowerShell system, service, event, network, storage and remote administration checks.
Robocopy — memo sheet
Robocopy reference for copying, migrations, ACLs, restartability, performance, filters, logs, dry runs and exit-code interpretation.
SMTP, SPF, DKIM & DMARC — Cheat sheet
Reference for tracing mail delivery and diagnosing SMTP transport, SPF, DKIM, DMARC, alignment and reputation.
VMware — operating memo
VMware vSphere/ESXi operations reference for VMs, snapshots, datastores, networking, storage, services, logs and maintenance checks.
Windows network — diagnostic memo
Field workflow to isolate Windows network failures across link, DHCP, IP, DNS, routing, firewall and application layers.
WordPress — Express troubleshooting
Incident-focused WordPress reference for logs, plugins, themes, database, WP-CLI, cron, permalinks, SMTP, permissions and 500/critical errors.