Port 80 — HTTP

TCP well-known

What runs on port 80

Unencrypted web traffic. Still the default port a browser tries when no scheme is given.

Security considerations

Serve nothing here but a 301 redirect to HTTPS. Add HSTS so browsers stop trying port 80 at all.

Checking whether something is listening

# Linux / macOS — what is bound to the port
sudo lsof -i :80
sudo ss -lntp | grep :80

# Windows
netstat -ano | findstr :80
Get-NetTCPConnection -LocalPort 80

# is it reachable from outside?
nc -zv example.com 80
curl -v telnet://example.com:80

Freeing the port

# find the process, then stop it
sudo lsof -ti :80 | xargs kill        # Linux / macOS
netstat -ano | findstr :80            # note the PID, then:
taskkill /PID <pid> /F                    # Windows

Should this port be open to the internet?

Yes — that is what it is for. Make sure whatever is listening is something you intend to expose, and that it does nothing but redirect to HTTPS.

Quick reference

Frequently asked questions

Other common ports

• Port 20 — FTP data
• Port 21 — FTP control
• Port 22 — SSH / SFTP
• Port 23 — Telnet
• Port 25 — SMTP
• Port 53 — DNS
• Port 67 — DHCP server
• Port 68 — DHCP client
• Port 69 — TFTP
• Port 110 — POP3
• Port 123 — NTP
• Port 143 — IMAP
• Port 161 — SNMP
• Port 389 — LDAP
• Port 443 — HTTPS
• Port 445 — SMB
• Port 465 — SMTPS
• Port 514 — Syslog

All port numbers