Port Checker
Check if a TCP/UDP port is open or closed on any server
Common Ports Reference
Web Services
80- HTTP443- HTTPS8080- HTTP Alternative8443- HTTPS Alternative
Mail Services
25- SMTP587- SMTP (TLS)143- IMAP993- IMAP (SSL)110- POP3995- POP3 (SSL)
Database Services
3306- MySQL5432- PostgreSQL27017- MongoDB6379- Redis
Remote Access
22- SSH3389- RDP21- FTP23- Telnet
Security Note: Open ports can be security vulnerabilities. Only open ports that are necessary and ensure they're properly secured.
Frequently Asked Questions
What does it mean if a port is open?
An open port means a service is listening on that port and accepting connections. This is normal for services you want to be publicly accessible.
What does it mean if a port is closed?
A closed port means either no service is running on that port, or a firewall is blocking access. This could be intentional for security.
Why can't I check some ports?
Some ports may be blocked by your ISP or network firewall. Additionally, the remote server may have firewall rules blocking checks from certain IPs.
Is it safe to have ports open?
Open ports are necessary for services but can be security risks. Only open necessary ports and ensure services are properly secured and updated.
Want Automated Monitoring?
Get 24/7 monitoring with instant alerts when issues are detected.
Start Free Trial