Is Port Checker free to use?

Yes, Port Checker on DevHexLab is completely free. No login, no account, and no payment required.

Does Port Checker upload my data to a server?

No. Port Checker runs entirely in your browser using client-side JavaScript. Your data never leaves your device and is never sent to any server.

Can I use Port Checker offline?

Yes. Once the page is loaded, Port Checker works without an internet connection because all processing happens locally in your browser.

What category does Port Checker belong to?

Port Checker belongs to the "Developer Utilities" category on DevHexLab. UUIDs, QR codes, API testing, and network tools

Port Checker

Check if a port is open or closed on any host

portchecknetworkopenclosed

Port Lookup

Enter a port number (1–65535) to see what service it is associated with.

Port Ranges

Well-Known Ports

0 – 1023

Assigned by IANA. Require root/admin privileges.

Registered Ports

1024 – 49151

Registered with IANA for specific services.

Dynamic / Private

49152 – 65535

Ephemeral ports used by clients and private apps.

Why can't browsers scan ports?

Browsers cannot perform raw TCP connections to arbitrary ports due to security restrictions (CORS, same-origin policy, and sandboxing). Port scanning requires OS-level socket access.

CLI Alternatives

nmapnmap -p 22,80,443 example.com

nc (netcat)nc -zv example.com 443

curlcurl -v telnet://example.com:443

PowerShellTest-NetConnection example.com -Port 443

Well-Known Ports Reference

39 commonly used ports and their services.

Port	Service	Protocol	Description
20	FTP Data	TCP	File Transfer Protocol (data transfer)
21	FTP	TCP	File Transfer Protocol (control)
22	SSH	TCP	Secure Shell: encrypted remote access
23	Telnet	TCP	Unencrypted remote access (deprecated)
25	SMTP	TCP	Simple Mail Transfer Protocol
53	DNS	TCP/UDP	Domain Name System
67	DHCP	UDP	Dynamic Host Configuration Protocol (server)
68	DHCP	UDP	Dynamic Host Configuration Protocol (client)
80	HTTP	TCP	Hypertext Transfer Protocol
110	POP3	TCP	Post Office Protocol v3 (email)
143	IMAP	TCP	Internet Message Access Protocol (email)
194	IRC	TCP	Internet Relay Chat
443	HTTPS	TCP	HTTP Secure (TLS encrypted)
465	SMTPS	TCP	SMTP over TLS (email)
587	SMTP	TCP	SMTP (email submission)
993	IMAPS	TCP	IMAP over SSL (email)
995	POP3S	TCP	POP3 over SSL (email)
1433	MSSQL	TCP	Microsoft SQL Server
1521	Oracle	TCP	Oracle Database
2181	ZooKeeper	TCP	Apache ZooKeeper
2375	Docker	TCP	Docker daemon (unencrypted)
2376	Docker	TCP	Docker daemon (TLS)
3000	Dev Server	TCP	Common development server port (React, etc.)
3306	MySQL	TCP	MySQL Database
4200	Angular	TCP	Angular CLI dev server
5000	Flask	TCP	Python Flask default port
5432	PostgreSQL	TCP	PostgreSQL Database
5672	RabbitMQ	TCP	RabbitMQ message broker
6379	Redis	TCP	Redis in-memory database
8000	Dev Server	TCP	Common dev/API server port (Django, etc.)
8080	HTTP Alt	TCP	Alternative HTTP port
8443	HTTPS Alt	TCP	Alternative HTTPS port
8888	Jupyter	TCP	Jupyter Notebook server
9000	SonarQube	TCP	SonarQube / PHP-FPM
9200	Elasticsearch	TCP	Elasticsearch REST API
9300	Elasticsearch	TCP	Elasticsearch cluster communication
15672	RabbitMQ	TCP	RabbitMQ management UI
27017	MongoDB	TCP	MongoDB database
5601	Kibana	TCP	Kibana dashboard

Learn more

Step-by-step guide

How to Check If a Port Is Open

Step-by-step guide to testing TCP port connectivity for any host using the DevHexLab Port Checker tool.

In-depth article

How to Check If a Network Port Is Open

Open ports determine what services a server exposes. Learn what ports are, why checking them matters, and how to test connectivity to any host and port.

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