Port 69: TFTP
Port 69 is TFTP, a stripped-down file transfer used to load firmware, boot images, and switch configs. It has no authentication, so it is kept to trusted management networks.
| Port number | 69 |
|---|---|
| Service | Trivial File Transfer Protocol |
| Protocol | UDP |
| Category | File transfer |
| Default encryption | No |
How do I check whether port 69 is open?
Port 69 is UDP, which changes the answer: there is no handshake to complete, so nothing outside the host can prove the port is open. Asking the host itself is the reliable route.
| Question | Command | What to know |
|---|---|---|
| Is it open on a remote host? | sudo nmap -sU -p 69 example.com | UDP has no handshake, so there is nothing to complete. nmap infers the state from whether an ICMP port-unreachable comes back, needs root, and is slow and easy to misread. A silent port may be open, filtered, or simply not replying to a probe it does not recognise. |
| What is listening locally? | ss -ulnp | grep ':69 ' | Shows the UDP socket bound to port 69. This is the reliable way to answer the question, because you are asking the host itself rather than guessing from outside. |
Replace example.com with the host you are testing. A blocked port and a port with nothing listening on it look identical from the outside, so if a service should be running, check locally before blaming the firewall.
Frequently asked questions
What is port 69 used for?
Port 69 is TFTP, a stripped-down file transfer used to load firmware, boot images, and switch configs. It has no authentication, so it is kept to trusted management networks.
Is port 69 TCP or UDP?
Port 69 (TFTP) uses UDP.
Is port 69 secure?
Port 69 is not encrypted by default. Where possible, use an encrypted alternative or tunnel it over TLS or a VPN.
Should I open port 69 on my firewall?
Only if you specifically need TFTP. Expose it to the smallest set of trusted sources, and never open database or Windows-service ports to the whole internet.