Port443/TCP

https

Port

443

Protocol

TCP

What is port 443?

Port 443/TCP is a Well-Known port, assigned by IANA for widely recognized services. It is associated with the https service.

http protocol over TLS/SSL

Useful commands

nmapnmap -p 443 -sV example.com

netcatnc -zv example.com 443

curlcurl -v https://example.com:443/

telnettelnet example.com 443

bash(echo > /dev/tcp/example.com/443) 2>/dev/null

Firewall commands

UFWAllow

sudo ufw allow 443/tcp

Deny

sudo ufw deny 443/tcp

iptablesAllow

sudo iptables -A INPUT -p tcp --dport 443 -j ACCEPT

Deny

sudo iptables -D INPUT -p tcp --dport 443 -j ACCEPT

firewalldAllow

sudo firewall-cmd --permanent --add-port=443/tcp

WindowsAllow

netsh advfirewall firewall add rule name="Open Port 443" dir=in action=allow protocol=TCP localport=443

Security Risks

Incorrect TLS/SSL configuration
Man-in-the-Middle attacks if certificate is invalid
Protocol implementation vulnerabilities
Exposure of web services with weak authentication

Frequently Asked Questions

What service runs on port 443/TCP?

Port 443/TCP is associated with the https service. http protocol over TLS/SSL

Is it safe to expose port 443 to the Internet?

It depends on the service and configuration. Port 443 (https) is a Well-Known port. If you need to expose it, keep the service updated, use strong authentication, and configure a firewall. It's always recommended to restrict access by IP when possible.

How do I check if port 443 is open?

You can use nmap: `nmap -p 443 -sV example.com`, netcat: `nc -zv example.com 443`, or the bash command: `(echo > /dev/tcp/example.com/443) 2>/dev/null && echo "Open" || echo "Closed"`.

How do I open or close port 443 on my firewall?

On Linux with UFW: `sudo ufw allow 443/tcp` (open) or `sudo ufw deny 443/tcp` (close). With iptables: `sudo iptables -A INPUT -p tcp --dport 443 -j ACCEPT`. On Windows: `netsh advfirewall firewall add rule name="Open Port 443" dir=in action=allow protocol=TCP localport=443`.

What applications and services use port 443?

Port 443/TCP is used by the https service. Specific uses depend on the software and configuration. Check our related tools section for more information.