Port 80: HTTP

What is port 80 used for?

Unencrypted web traffic.

Should port 80 be open?

Usually open to the internet. This port is meant to be reachable publicly on servers that offer the service. Keep 80 open on web servers so visitors are redirected (301) to HTTPS, and so Let’s Encrypt HTTP-01 validation works.

See what is listening on port 80

# Linux
sudo ss -tlnp | grep ':80 '

# macOS
sudo lsof -nP -i TCP:80 -sTCP:LISTEN

# Windows (PowerShell)
Get-NetTCPConnection -LocalPort 80 -State Listen

Open or block port 80 in a firewall

# Ubuntu / Debian (ufw)
sudo ufw allow 80/tcp
sudo ufw deny 80/tcp

# Windows (PowerShell, as administrator)
New-NetFirewallRule -DisplayName "Port 80" -Direction Inbound -Protocol TCP -LocalPort 80 -Action Allow

On cloud servers, also open the port in the provider’s security group or network firewall. At home, a service behind a router needs a port-forwarding rule to the device’s local IP.

Test it from outside

A port can be open on the server but blocked upstream. The Port Checker connects from the internet, so it shows what the world sees. From your own machine, use nc -vz example.com 80 (macOS/Linux) or Test-NetConnection example.com -Port 80 (Windows).