Port 443 — HTTPS (TCP)
What is Port 443?
Bezpieczny HTTP (SSL/TLS)
This is a well-known port (0–1023) commonly used by core services like HTTPS. · RFC 9110, RFC 8446
When do you need Port 443 open?
Open on any server serving content over HTTPS — websites, REST APIs, WebSocket connections, and modern web apps. This is the standard for encrypted web traffic and is rarely a reason to leave closed.
Common uses and software
- Apache HTTP Server
- Nginx
- Caddy
- Microsoft IIS
- Cloudflare
- All modern web browsers
Security
Port 443 must be open for any HTTPS web service. Ensure your TLS certificate is valid and issued by a trusted CA. Enforce TLS 1.2 as the minimum (TLS 1.3 preferred). Disable SSLv3, TLS 1.0, and TLS 1.1. Enable HSTS with a long max-age and include subdomains. Monitor certificate expiry to prevent outages.
Is Port 443 safe?
An open port increases your attack surface. Safety depends on how HTTPS is configured.
Keep HTTPS up to date with security patches. Require strong authentication and restrict access to the minimum necessary IP addresses.
Test connectivity for Port 443 on any host.
How to Open Port 443
To allow incoming connections to Port 443 (HTTPS) from outside your network, configure your firewall and add a port forwarding rule on your router pointing to your device's local IP address.
Open Windows Defender Firewall → Advanced Settings → Inbound Rules → New Rule → Port → TCP → Specific local ports: 443 → Allow the connection → Name and save the rule.
netsh advfirewall firewall add rule name="Open Port 443" dir=in action=allow protocol=tcp localport=443sudo ufw allow 443/tcpsudo iptables -A INPUT -p tcp --dport 443 -j ACCEPTLog into your router (192.168.1.1 or 192.168.0.1) → Port Forwarding → Add a new rule: Protocol TCP, External port 443, Internal IP: your device's local IP, Internal port 443 → Save.
How to close Port 443
If you do not need HTTPS, block this port in your firewall or router.
To block port 443 on Windows, run the following command in PowerShell or Command Prompt (as Administrator):
netsh advfirewall firewall add rule name="Block Port 443" dir=in action=block protocol=tcp localport=443sudo ufw deny 443/tcpsudo iptables -A INPUT -p tcp --dport 443 -j DROPRemove or disable any port forwarding rule for Port 443.
Frequently Asked Questions
What is Port 443 used for?▾
Port 443 is the default TCP port for HTTPS. It is used by servers and applications that need to accept incoming connections for this service. Whether you need it open depends on whether you are actively running a HTTPS server — if not, it should remain closed to reduce your attack surface.
Is Port 443 safe to keep open?▾
An open Port 443 increases your attack surface. If you are not actively running HTTPS, close this port in your firewall and remove any port forwarding rules. If HTTPS must be accessible, restrict access to known IP ranges, keep the service software updated with security patches, and use strong authentication.