PowerShell — Essential commands
Field reference for PowerShell system, service, event, network, storage and remote administration checks.
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Library
Cheat sheets
Windows network — diagnostic memo
Field workflow to isolate Windows network failures across link, DHCP, IP, DNS, routing, firewall and application layers.
View →DNS — memo form
DNS reference for records, resolvers, authoritative servers, delegation, caching and Active Directory zones.
View →SMTP, SPF, DKIM & DMARC — Cheat sheet
Reference for tracing mail delivery and diagnosing SMTP transport, SPF, DKIM, DMARC, alignment and reputation.
View →Active Directory — Essential Controls
Active Directory operations reference covering identity, replication, FSMO, DNS, Kerberos, GPO, time, secure channel and health checks.
View →VMware — operating memo
VMware vSphere/ESXi operations reference for VMs, snapshots, datastores, networking, storage, services, logs and maintenance checks.
View →Microsoft 365 — memo administration
Microsoft 365 administration reference for Entra identity, Exchange Online, SharePoint/OneDrive, Teams, Intune, PowerShell, mail traces and security checks.
View →HTTP — essential codes and headers
HTTP reference for methods, status codes, redirects, headers, caching, CORS, security and TLS/web troubleshooting.
View →Network ports — memo form
Reference of common ports, protocols and troubleshooting context; a known port never means it should be exposed to the Internet.
View →FortiGate — diagnostic memo
FortiGate CLI reference for system state, interfaces, ARP, routing, sessions, policy/NAT, SD-WAN, IPsec and debug flow.
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