Port 2376 — Docker API (TLS)

TCP registered

What runs on port 2376

The Docker daemon API with TLS client certificate authentication.

Security considerations

Still grants full host control to whoever holds a certificate. Treat those certificates like root passwords.

Checking whether something is listening

# Linux / macOS — what is bound to the port
sudo lsof -i :2376
sudo ss -lntp | grep :2376

# Windows
netstat -ano | findstr :2376
Get-NetTCPConnection -LocalPort 2376

# is it reachable from outside?
nc -zv example.com 2376
curl -v telnet://example.com:2376

Freeing the port

# find the process, then stop it
sudo lsof -ti :2376 | xargs kill        # Linux / macOS
netstat -ano | findstr :2376            # note the PID, then:
taskkill /PID <pid> /F                    # Windows

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 80 — HTTP
• Port 110 — POP3
• Port 123 — NTP
• Port 143 — IMAP
• Port 161 — SNMP
• Port 389 — LDAP
• Port 443 — HTTPS
• Port 445 — SMB
• Port 465 — SMTPS

All port numbers