Ping / Port Checker
Check if a specific port is open on any host. View latency, service name, and banner info.
Input
Common Ports
Results
Enter a host and port, then click Check.
Well-known ports cheat sheet
| Port | Protocol | Service |
|---|---|---|
| 22 | TCP | SSH (remote shell + SFTP) |
| 25 | TCP | SMTP (email relay, between mail servers) |
| 53 | UDP/TCP | DNS |
| 80 | TCP | HTTP |
| 110 | TCP | POP3 (legacy email retrieval) |
| 143 | TCP | IMAP (modern email retrieval) |
| 443 | TCP | HTTPS |
| 465 | TCP | SMTPS (SMTP over TLS) |
| 587 | TCP | SMTP submission (client → mail server) |
| 636 | TCP | LDAPS |
| 993 | TCP | IMAPS (IMAP over TLS) |
| 3306 | TCP | MySQL / MariaDB |
| 5432 | TCP | PostgreSQL |
| 6379 | TCP | Redis |
| 8080 | TCP | HTTP alternate (common dev server) |
| 8443 | TCP | HTTPS alternate |
| 27017 | TCP | MongoDB |
Open vs Closed vs Filtered — what your result means
- Open — host accepted the TCP handshake. A service is listening, and the network path allows it. Good.
- Closed — host responded but no service on that port. The OS sent a
RSTpacket. Means: the host exists, is reachable, just nothing listening on this specific port. - Filtered — no response within timeout. A firewall is silently dropping packets. Most common cause: misconfigured security group (AWS), NSG (Azure), or firewalld (Linux). Second most common: the port is open to some source IPs but not yours.
Filtered is the ambiguous case — the port may or may not have a service. From your perspective, indistinguishable from "closed by firewall rule."
Frequently Asked Questions
How do I check if a port is open on a server?
Enter a host and port — the checker attempts a TCP connection and reports open / closed / filtered. Common ports: 22 (SSH), 80 (HTTP), 443 (HTTPS), 3306 (MySQL), 5432 (Postgres), 6379 (Redis), 27017 (MongoDB). Great for firewall troubleshooting.
What's the difference between port open, closed and filtered?
Open = service is listening and accepted the TCP handshake. Closed = host responded but no service on that port. Filtered = no response (firewall likely dropping packets silently). Filtered is the most common symptom of a misconfigured security group.
How is this different from `nmap` or `telnet`?
Same idea — a TCP connect probe from the internet to your server. Nmap is richer (SYN scans, OS detection, service version probes). `telnet host port` is the Unix one-liner. This tool is a browser-based equivalent for quick checks.
Can I scan a range of ports?
Yes. Enter ports as a list (22,80,443) or range (1-1024). Bulk mode reports all results. Scan responsibly — run only against hosts you own or have permission to test.
Why does port 443 show open even though my site is down?
Open means TCP accepts connections. The service behind it (Apache, nginx, your app) might still be broken at the HTTP layer (500 error, hung worker, wrong cert). Combine with our Uptime Checker for HTTP-level status.
Smarter quality checks. Faster deployments.
Better apps.
