Practical technology help for homes and small businesses, from someone who knows how to make it work. Based in Martinez, serving Contra Costa County.
Practical IT guides, cheatsheets, and references from Jeremiah Ellington, drawn from more than 20 years of IT work in public sector and higher education.
Guides, cheatsheets & recommendations
Practical guides for homeowners, homelab builders, IT pros, and small businesses, written by Jeremiah Ellington, an IT professional with more than 20 years of experience. Each guide says who it's for, what software versions it covers, and when it was last reviewed.
Backups & Disaster Recovery · Start here
What the 3-2-1 backup rule really means, how backups differ from sync, how to set recovery goals, and how to build and test a backup plan that survives disk failure, theft, and ransomware, for homes and small businesses.
Networking & Wi-Fi · Start here
How a dependable network fits together: routers vs. firewalls, switches, VLANs, Wi-Fi, PoE, guest networks, firewall rules, DNS, remote access, and monitoring, with plans for homes and small offices.
Cloud & Microsoft 365 · Start here
The settings that matter most when a small office runs on Microsoft 365: admin and emergency accounts, MFA, email authentication, shared mailboxes, sharing, backups, onboarding and offboarding, plus a short Exchange Online PowerShell toolkit.
Homelab & Virtualization · Start here
Plan, build, and run a single-node Proxmox VE homelab: hardware, storage, networking, installation, VMs vs. containers, backups, and security, plus the mistakes to avoid.
Cybersecurity & Privacy · Start here
A prioritized security checklist for small businesses without IT staff: MFA, password managers, updates, endpoint protection, backups, email security, admin accounts, remote access, logging, incident response, and vendor security.
Website Hosting & Development · Start here
Domains, DNS, security certificates (TLS), and every kind of hosting explained in plain terms (shared, managed WordPress, VPS, managed cloud, static, and React/Next.js platforms), with a decision framework, honest cost and lock-in notes, and recommended setups for common small-business situations.
Proxmox, virtual machines, containers, and building a lab you can learn on.
Routers, firewalls, switches, VLANs, and Wi-Fi that stays up.
Practical security for households and small businesses without a security team.
Backups you can actually restore, and a plan for the bad day.
Troubleshooting, upgrades, and choosing hardware that lasts.
Hosting, domains, DNS, TLS, and keeping a small-business site healthy.
Accounts, devices, help desk, and the basics a small office needs.
Microsoft 365, Entra ID, and cloud services for small teams.
Domain controllers, DNS, replication, and planned changes to on-premises Active Directory.
Plain-English posts on using AI tools safely at home and at work, newest first.
Printable command references for the tools IT people use every day.
How to choose hardware and services, with honest trade-offs.
IT tool
Network and broadcast addresses, usable host range, wildcard and binary masks for any IPv4 address and prefix, with correct /31 and /32 handling and a subnet split helper.
IT tool
Recover a Type 7 password from a configuration you manage. Type 7 is reversible obfuscation, not encryption. Read the warning before you use it.
IT tool
Convert a subnet mask or prefix to a Cisco wildcard mask, or check any ACL address and wildcard, including noncontiguous ones, and test which addresses it matches.
IT tool
Practice subnetting without a chart: enter an IPv4 address and prefix, then reveal the interesting octet, increment, block, network, broadcast and usable range one step at a time, or test yourself on random questions.
PacketLife.net · by Jeremy Stretch
30 printable PDF references for networking, shared with credit to the author.
AI · How-to
Where Microsoft's own settings turn Copilot off in Word, Excel, PowerPoint, OneNote and Outlook, what each setting covers, and where it can't be turned off, as of October 30, 2026.
AI · Explainer
What to keep out of an AI chatbot, how personal and work accounts differ, the privacy settings Claude, Copilot and Gemini document, and where to check ChatGPT's, as of October 29, 2026.
Website Hosting & Development
What a TLS certificate is and how a browser or server decides to trust one: key pairs, signing requests, the subject and SAN, key usage, chains to a trusted root, validity, revocation, and where the certificate fits in the TLS handshake.
Active Directory
How Group Policy works in a single Active Directory domain: local and domain policy, processing order, filtering, the Central Store, backup and restore, troubleshooting, and the change-control habits that keep a policy change from becoming an outage.
Cheatsheet
OpenSSL commands for reading certificates, requests, CRLs and PFX files, checking a chain, matching a key to its certificate, and testing a live TLS server with s_client, organised around four everyday jobs.
Cheatsheet
The Windows tools for finding, checking, requesting and installing certificates, organised around four everyday jobs: renewing a server certificate, fixing an untrusted chain, moving a certificate to a new server, and publishing a template on an AD CS issuing CA.