80/TCPHTTP
Web · Well-known port · OSI layer 7
Unencrypted websites. Today, mainly needed for redirects to HTTPS and Let’s Encrypt validation (HTTP-01).
IANA: officially registered as http
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Port 80: Check and open the HTTP port
Port 80 is the default port for HTTP, the web’s unencrypted protocol. Here you’ll find key details about the port and ready-to-use firewall commands for your server.
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Ports
Firewall rule (inbound)
Firewall commands
Open port
sudo ufw allow 80/tcpNotes on ufw
For Ubuntu and Debian. ufw creates the rule for both IPv4 and IPv6. If ufw is disabled, allow SSH first (sudo ufw allow 22/tcp), then enable it with sudo ufw enable, or you'll lock yourself out.
On a ZAP-Hosting VPS with an active network firewall, you also need to allow the port in the Customer Panel.
Port 80 explained
What is port 80 used for?
Purpose
A web server receives HTTP requests on port 80. If you enter a domain in your browser without https://, the first request often still goes to port 80. Today, the port is therefore mostly used to redirect visitors to HTTPS. Let’s Encrypt also uses port 80 for its HTTP-01 challenge to verify that you control the domain before issuing a certificate.
Origin and standard
HTTP originated at CERN in the early 1990s as a protocol for the World Wide Web. HTTP/1.0 was described in RFC 1945, and HTTP/1.1 initially in RFC 2068 and RFC 2616. Today, RFC 9110 covers HTTP semantics and RFC 9112 covers HTTP/1.1. IANA lists port 80 as a Well-Known Port named “http”.
Typical use
- Redirecting HTTP to HTTPS (status code 301 or 308)
- HTTP-01 challenge from Let’s Encrypt and other ACME services
- Web servers on internal networks or in test environments without a certificate
- Reverse proxies that receive and forward all requests on port 80
Security
Everything sent over port 80 is unencrypted and can be read or modified in transit. Never send passwords, form data, or session cookies over it. Use port 80 only to redirect to HTTPS, and enable HSTS so browsers subsequently connect directly to port 443. You can leave port 80 open as long as it only handles the redirect and the ACME challenge.
More ports
Related ports
These ports are often part of the same setup. Click one to see its explanation and firewall commands.
View all well-known ports and the complete IANA list
Port list source: IANA Service Name and Transport Protocol Port Number Registry, as of October 22, 2026. iana.org
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FAQ
Frequently asked questions
Quick answers about port 80.
HTTP on port 80 uses TCP. IANA has also reserved the port for UDP, but UDP 80 is not used in practice. A TCP rule is therefore enough in the firewall.
To open the port with ufw, use sudo ufw allow 80/tcp. With firewalld, use sudo firewall-cmd --permanent --add-port=80/tcp followed by sudo firewall-cmd --reload.
In most cases, yes. Visitors who enter the domain without https:// first reach port 80 and need the redirect there. The Let’s Encrypt HTTP-01 challenge also requires port 80 for certificate renewal.
An open port alone is not a risk. It becomes dangerous when sensitive data is sent over HTTP or an outdated application is running behind it. Limit port 80 to redirects to HTTPS to keep the attack surface small.
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