Check-Host.cc

A TCP port checker is a diagnostic tool used to determine if a specific communication port on a network device (such as a server or router) is open and capable of receiving traffic.

While an HTTP monitor operates at the application layer to verify website content and response codes, a TCP port checker works at the transport layer, focusing strictly on the ability to establish a connection.
The tool can be used with live data over 60 seconds too. For that use the repeat button.

Examples:
1.1.1.1:80
https://check-host.cc:443
8.8.8.8:53

Commonly Used TCP Ports

A list of the most frequent destination ports encountered in modern network monitoring and firewall configuration.

Port	Service	Description
20	FTP Data	Used for transferring actual file data in Active FTP mode.
21	FTP Control	Used for sending commands and login credentials to FTP servers.
22	SSH	Secure Shell; used for secure remote login and file transfers (SFTP).
23	Telnet	Legacy plaintext remote login; largely replaced by SSH for security.
25	SMTP	Simple Mail Transfer Protocol; used for routing email between servers.
53	DNS	Domain Name System; resolves hostnames to IP addresses via TCP.
80	HTTP	Standard unencrypted web traffic; now often redirects to HTTPS.
110	POP3	Post Office Protocol v3; used by email clients to retrieve messages.
143	IMAP	Internet Message Access Protocol; used for accessing email on a server.
443	HTTPS	HTTP over SSL/TLS; the standard for secure web browsing and APIs.
445	SMB/CIFS	Server Message Block; used for file sharing and printing in Windows.
465	SMTPS	Secure SMTP; used for encrypted email transmission.
587	SMTP Submission	Modern port for mail clients to submit outgoing mail securely.
993	IMAPS	IMAP over SSL; encrypted access to email messages.
995	POP3S	POP3 over SSL; encrypted retrieval of email messages.
1433	MSSQL	Microsoft SQL Server; default port for database connections.
3306	MySQL	Standard port for MySQL and MariaDB database communication.
3389	RDP	Remote Desktop Protocol; used to remotely control Windows machines.
5432	PostgreSQL	Default port for PostgreSQL database server connections.
8080	HTTP Alternate	Commonly used for proxy servers, caching, or web apps in development.