What uses port 69
TFTP (Trivial File Transfer Protocol) has no authentication and no directory listing. It is used for PXE network booting, loading firmware and configs onto switches, routers and IP phones. Never expose it outside a trusted network: anyone who can reach it can download, and sometimes upload, files.
Should port 69 be open to the internet?
Keep private. Never expose this port to the internet. Keep it on localhost, a private network or behind a VPN or SSH tunnel.
Check what is listening on port 69
sudo ss -lunp 'sport = :69'sudo lsof -nP -iUDP:69Get-NetUDPEndpoint -LocalPort 69
netstat -ano | findstr :69No output means nothing is listening. If a service should be, check that it is running and which address it binds to: 127.0.0.1 only accepts local connections, 0.0.0.0 or :: accepts them on every interface.
Allow port 69 from trusted networks only
The examples allow 69 only from 10.0.0.0/8; replace it with your own private network, office IP or VPN range.
sudo ufw allow from 10.0.0.0/8 to any port 69 proto udp
# Close it again:
sudo ufw delete allow from 10.0.0.0/8 to any port 69 proto udpsudo firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="10.0.0.0/8" port port="69" protocol="udp" accept'
sudo firewall-cmd --reloadNew-NetFirewallRule -DisplayName "TFTP 69/UDP" -Direction Inbound -Protocol UDP -LocalPort 69 -Action Allow -RemoteAddress 10.0.0.0/8On AWS, Google Cloud and Azure, also allow the port in the security group or network firewall rules; host firewalls and cloud firewalls are separate.
Test port 69 from another machine
nc -zvu example.com 69 # UDP has no handshake, so "open" isn't conclusiveRelated ports
- Port 67 (DHCP server): where DHCP servers listen for requests from devices that need an IP address.
- Port 21 (FTP): the control port of FTP, the File Transfer Protocol.
- Port 22 (SSH): used by SSH for secure remote logins, SFTP, SCP and Git over SSH.
More file sharing ports
20 (FTP data) , 139 (NetBIOS Session) , 445 (SMB) , 873 (rsync) , 990 (FTPS) , 2049 (NFS) . See all ports in the port lookup.
Sources
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Frequently asked questions
What is port 69 used for?
Port 69 is used by TFTP, a minimal file transfer protocol for network booting and device firmware. TFTP (Trivial File Transfer Protocol) has no authentication and no directory listing. It is used for PXE network booting, loading firmware and configs onto switches, routers and IP phones. Never expose it outside a trusted network: anyone who can reach it can download, and sometimes upload, files.
Is it safe to open port 69?
Never expose this port to the internet. Keep it on localhost, a private network or behind a VPN or SSH tunnel. Allow it only from the networks that need it, as in the firewall examples on this page.
How do I check if port 69 is open?
On the server, list listening sockets with "sudo ss -lunp 'sport = :69'" on Linux or "sudo lsof -nP -i :69" on macOS. From another machine, UDP has no handshake, so a port scan can’t reliably tell whether it is open; test with a real client for the service instead.