How do I check if port 8443 is open?

Enter your public IP or hostname into the scanner tool and click Check. A sub-second raw TCP socket handshake will be initiated from our edge server to port 8443 on your target. If the 3-way handshake finishes with SYN-ACK, the port is OPEN. If an RST packet is returned, the host is reachable but the port is CLOSED. If packets time out without response, the port is FILTERED by an ISP or firewall.

Is port 8443 safe to expose to the public internet?

Port 8443 is generally safe to expose when running standard, patched services with strong authentication. However, always ensure your software is updated and access control policies are strictly enforced.

Why does port 8443 show as closed or filtered?

If port 8443 reports CLOSED or FILTERED, confirm that: 1) Your service is actively running and bound to 0.0.0.0 (not just localhost/127.0.0.1); 2) Your router has a port forwarding rule directing external port 8443 to your machine's local IP; 3) Your operating system firewall (Windows Defender Firewall, ufw, or iptables) allows incoming connections on port 8443.

PORT 8443 TCP Web Low Risk

Port 8443 (HTTPS-Alt (Secure Web Alternative)) Open Check

Q: What is port 8443 used for?

Port 8443 is the standard TCP port used for HTTPS-Alt (Secure Web Alternative). It is commonly used by Apache Tomcat SSL, UniFi Network Controller, Plesk, cPanel. Common alternative port for secondary SSL/TLS web applications and administration interfaces.

Common alternative port for secondary SSL/TLS web applications and administration interfaces.

Live Socket Reachability Probe

Pre-configured for Port 8443

Port Scanner

Quick:

Recent Probes 0

Stored locally in browser • 0 logs on server

No recent scans recorded.

Target hosts and tested ports will appear here automatically for fast 1-click re-testing.

Auto-prunes oldest probes beyond 10 entries (FIFO)

Port Specifications & Network Behavior

Standard Port Number 8443

Primary Service HTTPS-Alt (Secure Web Alternative)

Transport Protocol TCP

Traffic Classification Web

Residential ISP Status Typically unrestricted by consumer ISPs

Security Exposure Low Suitable for public internet hosting with authentication

Security Advisory: HTTPS-Alt (Secure Web Alternative) (Port 8443)

Encrypted transport. Enforce strong authentication if exposing administrative web consoles.

Port Forwarding & Troubleshooting Checklist

If port 8443 returns CLOSED or FILTERED, work through this verified diagnostic checklist:

1 Verify TLS certificate is assigned to port 8443 in application configuration.
2 Confirm host firewall permits inbound traffic on TCP 8443.
3 Verify target application process is active with 'netstat -ano | findstr :8443'.

Verify Host Is Listening Locally

Windows (PowerShell) netstat -ano | findstr :8443

Linux / macOS (Bash) ss -tulpn | grep :8443