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🛡️ RDP Security Warning

Why You Should Never Open RDP Port 3389 to the Internet

It takes two minutes to forward port 3389 and it works beautifully — for you, and for every automated scanner on the internet. This is the most common way small office servers get broken into, and the fix costs nothing.

✍️ Technical Anshu🪟 Windows RDP Safety⏱️ 6 minute read
🎥 Watch the full video — remote access with zero open ports, the safe Tailscale way

Forwarding port 3389 is the oldest trick for reaching an office PC from home, and it is quietly responsible for a huge share of small-business ransomware cases. The moment that port opens, your PC starts answering login attempts from strangers — automated bots that scan the entire internet continuously, find every exposed RDP service, and hammer it with password guesses around the clock. Your password does not have to be weak today. It only has to fall once — to a leak, a reused password, or plain patience.

Event Viewer — Security Log on an Exposed RDP Server
Failed logon — unknown user, foreign IPEvent 4625
Failed logon attempts in the last 24 hours4,318 NON STOP
Usernames being triedadmin, user, test, server…
Successful logon by an account you do not knowEvent 4624 TOO LATE
☝️ What the log of an internet-facing RDP server really looks like — thousands of silent attempts every single day
1

Understand How the Attack Actually Works

  1. Discovery is automatic. Public scanning services index open RDP ports across the internet. Your new forward can be found within minutes to hours — there is no hiding by obscurity
  2. Guessing is automated. Bots try common usernames with huge password lists, day and night, without any human watching
  3. One success is total. A valid RDP login is not a peek — it is your full desktop, your files, your Tally data, and usually a path into the rest of the office network
  4. The ending is usually ransomware or quiet data theft. This pattern — exposed RDP as the entry point — is a documented favourite against small offices precisely because it keeps working
2

Check Whether You Are Exposed Right Now

  1. Open your router's port forwarding / virtual server page and look for any rule sending 3389 (or any port) to an office PC
  2. Also check for a DMZ entry pointing at a PC — a DMZ exposes far more than RDP
  3. On the PC itself, open Event Viewer, then Windows Logs, Security, and filter for event 4625 (failed logon). Thousands of failures from addresses you do not recognise means the port is being attacked already
  4. See a successful 4624 logon for an account or time you do not recognise? Treat it as a break-in — change passwords from a clean machine and get professional help. Do not just close the port and relax
3

Close the Door First, Then Rebuild Access Safely

  1. Delete the 3389 forwarding rule (and any DMZ entry) in the router. This takes one minute and ends the exposure
  2. Change the office PC's Windows password to a long, unique one — the old one has been guessed at thousands of times
  3. Make sure Windows is fully updated. RDP has had serious vulnerabilities in the past, and unpatched exposed servers are targeted first
  4. Only now set up the replacement access from Fix 4 — never leave a gap where someone re-opens the port just to get work done
4

Things That Help but Do Not Make Open RDP Safe

These are good habits — but understand their limits honestly.

  1. Changing the RDP port to something unusual reduces noise, but scanners find RDP on any port. It is camouflage, not a lock
  2. Network Level Authentication (NLA) and account lockout policies raise the cost of guessing — keep them on, but they do not stop a leaked password from working
  3. A strong password is essential and still a single point of failure. Ports get attacked forever; passwords get reused, shared and phished
  4. The correct principle — RDP itself can stay. What must go is its direct exposure. It should only ever be reachable through a private, authenticated network
5

The Safe Replacement — RDP Inside a Private Network ⭐

  1. Install Tailscale on the office PC and on the devices that need access, as shown in the video
  2. Connect Remote Desktop to the PC's private 100.x Tailscale address. From the internet, the office now shows no open ports at all — there is nothing for a scanner to find
  3. Access is controlled by your Tailscale account with its own sign-in and two-factor authentication, and you can remove a lost device from the admin console in seconds
  4. For larger setups, the same principle scales — a proper VPN or an RD Gateway also puts RDP behind an authenticated door. The tool matters less than the rule: RDP never faces the internet alone
⚠️ If a guide or a technician suggests forwarding 3389 as the final solution, that advice is out of date. It was common practice years ago; today it is the first thing incident responders look for after a small-office break-in. Convenience for one evening is not worth the office's accounts data.

🎥 Watch the Safe Method in the Full Video

The video sets up full RDP access to an office PC with the router showing zero open ports — the way remote access should look.

▶️ Watch Full Video
❓ Frequently Asked Questions

I only opened 3389 for one day. Was that long enough to be found?

Quite possibly. Internet-wide scanners sweep address ranges continuously, and new open ports are typically discovered within hours, sometimes much faster. One day of exposure means one day of automated password guessing. If the port was open, close it, set a fresh strong password, and glance through the security log for unfamiliar successful logons.

Is RDP itself unsafe, or only the way it was connected?

RDP between your own devices on a private network is a normal, widely used tool. The danger is publishing it directly on the internet, where anyone on Earth can attempt to log in. Keep RDP, remove the exposure — run it inside Tailscale, a VPN, or behind an RD Gateway.

What if my office software vendor insists on a public port for support?

Ask them to connect through your private network instead — for example by joining your Tailscale network as an invited device for the support session, then being removed afterwards. A permanent public port opened for occasional support is permanent risk for a temporary need, and most vendors will accept the safer route when asked.

This guide is based on the Technical Anshu no static IP remote access video • Stuck on any step? Ask in the video comments — help is available there 🙏