TFTP
What is Port 69?
Port 69 is used by the Trivial File Transfer Protocol (TFTP), a simplified file transfer protocol that uses UDP instead of TCP. Defined in RFC 1350, TFTP provides basic read and write functionality without authentication, directory listing, or any of the advanced features of FTP. Despite its simplicity, TFTP is widely used in specific scenarios where lightweight file transfer is needed. Network equipment manufacturers commonly use TFTP for firmware updates and configuration file transfers on routers and switches. TFTP is also essential for PXE (Preboot Execution Environment) network booting, where diskless workstations download their operating system images from a TFTP server during the boot process.
Common Uses
- Network device firmware updates and configuration backups
- PXE network booting for diskless workstations
- VoIP phone provisioning and configuration
- Embedded system bootstrapping
Technical Details
Copy-paste commands to check port 69 (TFTP) from your terminal
Test connectivity
nmap -p 69 -sU -sV example.com
(echo > /dev/tcp/example.com/69) 2>/dev/null && echo "open" || echo "closed"
Open port in firewall
sudo ufw allow 69/udp
sudo iptables -A INPUT -p udp --dport 69 -j ACCEPT
sudo firewall-cmd --permanent --add-port=69/udp && sudo firewall-cmd --reload
Security Considerations
TFTP has no authentication or encryption whatsoever. Anyone who can reach a TFTP server can read or write files. Never expose TFTP to the internet. Restrict access to trusted management networks only. Use file system permissions to limit what TFTP can serve. Consider replacing TFTP with SFTP or HTTPS-based provisioning where possible.
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