Zero Trust Without the Buzzwords: Three Simple Fences You Can Build This Month

TL;DR: 

You don’t need a rip-and-replace to get safer. Start with three “fences”:

1. Separate the lanes (people, servers, gadgets).
2. Double-check admin access (MFA + healthy device).
3. Only open the few ports each lane truly needs.Do this, and you’ll stop a lot of threats from moving around—even if something goes wrong on one device.

What “Zero Trust” Really Means (in human terms)

Zero trust isn’t one product. It’s a way of not assuming anything is safe by default—you verify devices and people, and you limit what each thing can reach. Think of it like fire doors in a building: a small spark shouldn’t take down the whole floor.

Fence 1: Put People, Servers, and Gadgets in Their Own Lanes

Goal: If a guest laptop or a smart TV gets weird, it can’t wander into payroll or your file server.

Do this:

• Create three networks (VLANs/SSIDs): Users, Servers/Apps, Gadgets (IoT/OT).
• Keep Guest Wi-Fi internet-only—no peeking at company devices.
• Block “east-west” traffic by default between lanes. Allow intentional exceptions only.

Quick wins:

• Move printers, cameras, TVs, badge readers into Gadgets.
• Keep Servers/Apps behind the firewall; don’t let normal laptops talk to them directly unless needed.

Fence 2: Extra Check for Admin Tools (MFA + Healthy Device)

Goal: Only the right people on the right, healthy devices can touch sensitive tools (firewalls, servers, RMM, payroll, banking).

Do this:

• Turn on MFA everywhere that matters (email, admin portals, payroll/banking).
• Require a healthy device for admin access (patched OS, disk encrypted, EDR running).
• Prefer phishing-resistant sign-ins (passkeys/FIDO2) where supported.

Quick wins:

• Remove standing “global admin” rights. Use just-in-time elevation for maintenance windows.
• Put remote-management tools behind SSO with MFA; no direct logins hanging on the internet.

Fence 3: Only Open the Few Ports Each Lane Needs

Goal: Less is more. If the app only needs DNS and HTTPS, don’t leave anything else open.

Do this:

• Start default-deny between lanes; then allow only what’s required (e.g., Users → DNS/NTP/HTTPS; Gadgets → vendor cloud; Servers → backups).
• Document every “allow.” Give it an owner and a review date.

Quick wins:

• Close risky services at the perimeter (RDP/3389, SMB/445) unless absolutely required—and then restrict by source, time, and MFA.

Starter Map (copy this into your runbook)

Lanes:

• Users (laptops/workstations)
• Servers/Apps (file/app servers, line-of-business systems)
• Gadgets (printers, cameras, TVs, sensors, kiosks, OT)
• Guest (internet only)

Typical allows:

• Users → DNS(53), NTP(123), HTTPS(443)
• Users → Specific app ports on Servers/Apps (list them)
• Gadgets → Vendor cloud over HTTPS only
• Servers/Apps → Backup network/storage
• Guest → Internet only (client isolation on)

How to Roll This Out in 30 Days (no drama)

Week 1: Inventory & label

• List devices by lane (Users/Servers/Gadgets/Guest).
• Flag unknowns and anything exposed to the internet.

Week 2: Build the lanes

• Create VLANs/SSIDs, move devices, turn on guest isolation.
• Back up firewall config.

Week 3: Enforce the fences

• Default-deny between lanes, then add the minimal “allows.”
• Turn on MFA for admin tools and SSO apps.

Week 4: Verify & train

• Try a blocked path on purpose—confirm it’s blocked.
• Run a 15-minute tabletop: “Printer gets malware—what happens?”
• Share a 1-page cheat sheet with your team.

Common Pitfalls (and easy fixes)

• “We’ll segment later.” Do it now, even if it’s basic. Perfect is the enemy of shipped.
• Too many exceptions. Time-box them. If the exception still exists next month, re-approve or remove.
• Shadow admin tools. Anything that can log into lots of machines belongs behind SSO + MFA.

How You’ll Measure Progress

• Blocked lateral moves show up in logs (good!).
• Fewer critical alerts from EDR after segmentation.
• Faster patch windows because changes are scoped to a lane.

FAQ (quick answers for your team)

Is zero trust only for big companies? Nope. Lanes + MFA + minimal opens = meaningful risk drop for any size.

Do I need new hardware? Often, no. Many existing firewalls/switches support VLANs, rules, and MFA-protected portals.

Will this slow people down? Done right, no. It quietly stops problems from spreading while your users keep working.