Port 67: DHCP server
UDP 67 is the port for DHCP / BOOTP (server side). Never from the internet. It has no meaning outside a LAN.
| Service | DHCP / BOOTP (server side) |
|---|---|
| Protocol | UDP |
| Exposure risk | Medium: expose with care |
| Range | Well-known (0–1023): binding needs root/admin on Unix |
Port 67 is UDP-only. UDP has no handshake, so no online checker can reliably tell open from filtered; test with the service's own client.
What port 67 does
Clients broadcast DHCP requests from UDP 68 to UDP 67 to get an IP address, gateway and DNS servers. It only operates on the local network, or across subnets through a DHCP relay.
Should port 67 be open?
Never from the internet. It has no meaning outside a LAN.
Find what's listening on port 67
- Linux:
sudo ss -tulpn | grep :67 - macOS:
sudo lsof -nP -i :67 - Windows:
netstat -ano | findstr :67, then look up the PID in Task Manager.
Open or block it in a firewall
- ufw:
sudo ufw allow 67/udp(ordeny) - firewalld:
sudo firewall-cmd --add-port=67/udp --permanent && sudo firewall-cmd --reload - Windows:
New-NetFirewallRule -DisplayName "Port 67" -Direction Inbound -Protocol UDP -LocalPort 67 -Action Allow
Port assignment per the IANA Service Name and Transport Protocol Port Number Registry. Test several ports at once with the port scanner, or any port with the open port checker.
Questions about port 67
What is port 67 used for?
DHCP / BOOTP (server side). Clients broadcast DHCP requests from UDP 68 to UDP 67 to get an IP address, gateway and DNS servers. It only operates on the local network, or across subnets through a DHCP relay.
Is port 67 TCP or UDP?
UDP. DHCP server uses UDP port 67.
Is it safe to open port 67?
Medium: expose with care. Never from the internet. It has no meaning outside a LAN.
How do I check if port 67 is open?
Port 67 is UDP-only, which has no handshake, so an online TCP checker can't confirm it. Use the service's own client to test, and check what is listening locally with
ss -ulpn | grep :67 (Linux) or netstat -ano | findstr :67 (Windows).