Port 79: Finger
Port 79 is the Finger protocol, which returns basic information about a user on a remote system, such as whether they are logged in. It leaks account details by design and is almost always disabled on modern systems.
| Port number | 79 |
|---|---|
| Service | Finger protocol |
| Protocol | TCP |
| Category | Legacy protocols |
| Default encryption | No |
How do I check whether port 79 is open?
Port 79 carries TCP, so a connection either completes its handshake or it does not, which makes the check definitive.
| Question | Command | What to know |
|---|---|---|
| Is it open on a remote host? | nc -vz example.com 79 | A TCP handshake either completes or it does not, so netcat gives a definitive answer in one line. |
| Same check on Windows | Test-NetConnection example.com -Port 79 | Built into PowerShell. TcpTestSucceeded in the output is the answer; telnet is not installed by default on modern Windows. |
| What is listening locally? | ss -tlnp | grep ':79 ' | Lists the process bound to port 79 on Linux. On macOS use lsof -nP -iTCP:79 -sTCP:LISTEN, on Windows netstat -ano | findstr :79 |
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 79 used for?
Port 79 is the Finger protocol, which returns basic information about a user on a remote system, such as whether they are logged in. It leaks account details by design and is almost always disabled on modern systems.
Is port 79 TCP or UDP?
Port 79 (Finger) uses TCP.
Is port 79 secure?
Port 79 is not encrypted by default. Where possible, use an encrypted alternative or tunnel it over TLS or a VPN.
Should I open port 79 on my firewall?
Only if you specifically need Finger. Expose it to the smallest set of trusted sources, and never open database or Windows-service ports to the whole internet.