Whose servers can I scan?

Your own servers or those you have the owner’s permission to check.

Why is a port “filtered”?

Usually a firewall or router blocks the connection — there is no “open” or “closed” reply at all.

Can a firewall hide open ports?

Yes, so “filtered” does not always mean the port is closed.

How is “closed” different from “filtered”?

“Closed” — the server replied that there is no service. “Filtered” — there was no reply at all: a firewall dropped the connection.

Does the scanner see ports inside my network?

No. The check runs from the internet, so only ports reachable from outside are visible.

Online Port Scanner

Enter the IP or domain of your server, choose a port set and get the status of every port — open, closed or filtered.

Check result

What the port scanner shows

A short note on every field of the result. Details are in the sections below.

Port and service

The port number and what usually runs on it

Status

Open, closed or filtered

Port set

Popular or service ports

Export

Download the result as .csv

Your IP

Fill in your own IP in one click

Domain or IP

Either works

What is a port scanner

The scanner tries to connect to the server ports and shows the status of each: open, closed or filtered. The check runs from our server — the way your server is seen from the internet.

IP port scanner: which ports it checks

The ports are split into two sets — the same tabs as in the scanner. The list matches exactly what the tool checks.

Popular ports

Port	Service	Used for
21	FTP	File transfer
22	SSH	Remote server management
23	Telnet	Legacy unencrypted remote access
25	SMTP	Mail between servers
53	DNS	Name server
80	HTTP	Website without encryption
110	POP3	Receiving mail
143	IMAP	Mail access
443	HTTPS	Encrypted website
465	SMTPS	Encrypted mail sending
587	SMTP Submission	Sending mail from mail clients
993	IMAPS	Encrypted mail access
995	POP3S	Encrypted mail receiving
1080	SOCKS	Proxy server
3128	HTTP Proxy (Squid)	HTTP proxy
3306	MySQL	Database
3389	RDP	Windows Remote Desktop
5432	PostgreSQL	Database
8080	HTTP Alternate	Panels, test sites, proxies
8443	HTTPS Alternate	Control panels

Hidden and service ports

Port	Service	Used for
111	RPCbind	Linux RPC service used by NFS
123	NTP	Time synchronization
135	MS RPC	Windows remote procedure calls
139	NetBIOS	File sharing in legacy Windows networks
445	SMB	Windows file and printer sharing
1194	OpenVPN	VPN server
1433	MS SQL	Database
1521	Oracle DB	Database
1723	PPTP	Legacy VPN
2049	NFS	Network file system
2375	Docker API	Unencrypted Docker management
5900	VNC	Remote desktop
6379	Redis	Cache and queues
8000	HTTP Dev	Test and dev servers
8888	HTTP Alternate	Panels, Jupyter, proxies
9200	Elasticsearch	Search engine
10000	Webmin / NDMP	Webmin panel, backups
11211	Memcached	Cache
25565	Minecraft	Game server
27017	MongoDB	Database

What port statuses mean

Status	Meaning	What to do
Open	The service on the port accepts connections from the internet	Fine if the service must be reachable from outside. If not, close it
Closed	The server replied that nothing runs on the port	Nothing, if the service is not needed here
Filtered	No reply: a firewall drops the connection	Usually intended; if the port must work, check the firewall rules

How to check open ports online

1
Enter the IP or domain of your server — or click “My IP” to fill in your own address.
2
Choose a set: popular or service ports.
3
Click “Scan” and wait for the result.
4
Download the result as .csv if needed.

The check runs from our server — you see your server the way the internet sees it, not from your local network.

Why check open ports

Server security

Every open port is an entry point. Databases, caches and control panels open to the whole internet are a common cause of breaches.

Check after setup

Opened a port in the firewall or started a service — the scanner shows whether it is reachable from outside.

Diagnostics

A service does not respond — the scanner shows whether the port is closed, filtered by a firewall or the service is simply not running.

Check your own proxy server

If an app cannot connect to your proxy, check whether its port is open, e.g. 3128 or 1080.

Which ports should not stay open

Open 80 and 443 on a web server and 22 for SSH are fine. Close these to the internet or restrict them by IP:

databases — MySQL, PostgreSQL, MongoDB, Redis, Elasticsearch;
Docker API (2375);
RDP and VNC — better allow access only via VPN or from trusted IPs;
Windows file sharing — SMB (445) and NetBIOS (139);
unencrypted Telnet and FTP — replace them with SSH and SFTP.

Why a port is closed while the service runs

The service listens on 127.0.0.1 only and does not accept outside connections.
The port is closed by the server or hosting firewall.
The service runs on a different port.
The provider blocks the port — this happens with port 25.

Terms of use

Scan your own servers or servers you have the owner’s permission to check. Scanning other people’s servers without permission may violate hosting rules and the law.

Need a server of your own? VPS and dedicated servers — PSB Hosting.

Use cases