Port 1723: PPTP
Port 1723 is PPTP, an early Microsoft VPN protocol. Its encryption has been broken for years, so it should not be used where real security matters; modern deployments use OpenVPN, WireGuard, or IPsec instead.
| Port number | 1723 |
|---|---|
| Service | Point-to-Point Tunneling Protocol |
| Protocol | TCP |
| Category | Remote access |
| Default encryption | No |
How do I check whether port 1723 is open?
Port 1723 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 1723 | 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 1723 | 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 ':1723 ' | Lists the process bound to port 1723 on Linux. On macOS use lsof -nP -iTCP:1723 -sTCP:LISTEN, on Windows netstat -ano | findstr :1723 |
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 1723 used for?
Port 1723 is PPTP, an early Microsoft VPN protocol. Its encryption has been broken for years, so it should not be used where real security matters; modern deployments use OpenVPN, WireGuard, or IPsec instead.
Is port 1723 TCP or UDP?
Port 1723 (PPTP) uses TCP.
Is port 1723 secure?
Port 1723 is not encrypted by default. Where possible, use an encrypted alternative or tunnel it over TLS or a VPN.
Should I open port 1723 on my firewall?
Only if you specifically need PPTP. Expose it to the smallest set of trusted sources, and never open database or Windows-service ports to the whole internet.