🛡️ Port Scanner Simulator
Understand what runs on a network port and the risk of exposing it. Enter a port number for a plain-language explainer. This is an educational reference — it does not scan any host.
🔎 Look Up a Port
🛡️ Educational reference only — this does not scan any host. It never connects to, probes, or transmits to any machine. It simply looks up what commonly runs on a port and the risk of exposing it.
Common ports at a glance
| Port | Service | Risk |
|---|---|---|
| 20 | FTP-DATA | medium |
| 21 | FTP | high |
| 22 | SSH | medium |
| 23 | Telnet | high |
| 25 | SMTP | medium |
| 53 | DNS | medium |
| 80 | HTTP | medium |
| 110 | POP3 | medium |
| 143 | IMAP | medium |
| 443 | HTTPS | low |
| 445 | SMB | high |
| 3306 | MySQL | high |
| 3389 | RDP | high |
| 5432 | PostgreSQL | high |
| 8080 | HTTP-ALT | medium |
What is this Port Scanner Simulator?
It is a learning aid that explains network ports. Enter one or more port numbers and it tells you the service that typically listens there, the protocol, and how risky it is to expose that port to the internet — with the reasoning behind each rating.
Crucially, it performs no real scanning: nothing is sent to any machine. It is a static reference for understanding the attack surface of open ports, so you can reason about firewall rules and which services should never face the public internet.
❓ Frequently Asked Questions
Does this actually scan a computer or network?
No. This is a purely educational reference. It never connects to, probes, or transmits to any host — it simply looks up what a given port number commonly hosts and the security considerations of exposing it. To scan systems you own you would use a dedicated tool, and only with authorization.
What is a port, in plain terms?
A port is a numbered doorway on a computer that a particular network service listens on — like HTTPS on 443 or SSH on 22. Ports let one machine run many services at once, with each conversation routed to the right one by its port number.
Why are some ports flagged high-risk?
Because exposing them to the public internet invites attack. Telnet (23) sends everything in clear text, RDP (3389) is relentlessly brute-forced, and SMB (445) has been the vector for major worms and ransomware. Such services should sit behind a VPN or firewall, never open to the world.
What are ephemeral ports?
Ports in the 49152–65535 range are assigned temporarily by the operating system for the client side of outbound connections, then released. They are not fixed services, so seeing one is normal and expected — it is just your machine talking out, not something listening for the internet.