What port does DHCP use?
DHCP uses 67 and 68, and which one depends on what you are doing.
Server and client each have their own port, and both are UDP.
| Port | Protocol | Name | What it is for |
|---|---|---|---|
| 67 | UDP | DHCP server | Hands out IP addresses to clients on a local network. |
| 68 | UDP | DHCP client | The client side of DHCP address assignment. |
Exposing it
Two DHCP servers on one network cause address conflicts — a classic cause of "the internet is down" in small offices.
Checking it is listening
sudo lsof -i :67 # macOS, Linux
netstat -ano | findstr :67 # Windows
nc -zv host 67 # from elsewhereAn "address already in use" error on a port nothing appears to be holding usually means the socket is in TIME_WAIT rather than that a process has it — the ports reference covers that and the ephemeral range.
Frequently asked questions
What port does DHCP use?
DHCP uses ports 67, 68, and they do different jobs. 67: Hands out IP addresses to clients on a local network. 68: The client side of DHCP address assignment.
Is port 67 safe to expose to the internet?
Two DHCP servers on one network cause address conflicts — a classic cause of "the internet is down" in small offices.
How do I check whether DHCP is listening?
sudo lsof -i :67 on macOS or Linux, netstat -ano | findstr :67 on Windows. From another machine, nc -zv host 67 says whether anything answers.
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Port 67 in full · Port 68 in full · Every service · All port numbers