Port 1723PPTP
PPTP, or Point-to-Point Tunneling Protocol, is a VPN protocol developed by Microsoft to enable secure data transfer through encryption and encapsulation. While it historically allowed users to create secure communication tunnels over public networks, today it is largely considered outdated due to its well-known security vulnerabilities..
- transport
- tcp · udp
- in transit
- cleartext
- assignment
- official
- risk
- 4/10
- lookups
- 11,321
2 transports registered
payload readable on path
registered with iana
caution
rank 367 of 993 · top 37%
Technical Details
what runs on :1723Microsoft's Point-to-Point Tunneling Protocol (PPTP) is one of the earliest VPN protocols, designed to provide secure transmission of data over IP networks by encapsulating PPP packets inside GRE (Generic Routing Encapsulation) tunnels. Operating primarily on TCP port 1723 for control and GRE for data, it facilitates user authentication and encryption for remote connections to a VPN server.
The design of PPTP is relatively straightforward, relying on a combination of the PPP authentication framework, which supports protocols like PAP and MS-CHAP, and MPPE (Microsoft Point-to-Point Encryption) to achieve confidentiality. Its simplicity led to widespread adoption due to its native support across many Microsoft Windows systems without the need for additional software.
Despite its popularity, PPTP's reliance on TCP port 1723 and GRE makes it susceptible to network issues like packet filtering or NAT traversal difficulties. Modern networks frequently block or restrict GRE traffic, which can disrupt PPTP connections, and its outdated encryption methods no longer meet today's standards for secure communications.
Security Information
exposure of :1723risk score
4/ 10caution
worth attention. how exposed you are depends on configuration — don't leave it reachable from the internet without a reason.
security averages 3.8 across 216 ports — this one sits 0.2 above.
in transit
cleartext
credentials and payloads are readable by anyone on path
assignment
official
registered with iana for this service — scanners fingerprint it by number
reachable over
tcp · udp
udp is connectionless — source addresses are trivially spoofed and it is a reflection favourite
security overview
Common Vulnerabilities:
- Weak encryption algorithms such as MS-CHAPv2 susceptible to brute-force and dictionary attacks
- Susceptibility to Man-in-the-Middle attacks due to weak authentication challenge response mechanisms
- Vulnerability to GRE packet manipulation and session hijacking
- Lack of perfect forward secrecy, risking exposure if long-term keys are compromised
Common Mitigations:
- Avoid using PPTP where possible; opt for modern, securely designed VPN protocols (such as OpenVPN, IKEv2/IPSec, or WireGuard)
- Implement strong user authentication policies and require complex passwords
- Disable PPTP endpoints on network infrastructure
- Employ multi-factor authentication if PPTP must be used
- Monitor network traffic for suspicious PPTP-related activity and log VPN events thoroughly
Related Ports
the 8 most looked-up other ports in security — 216 ports carry that label.
| port | service | risk | |||
|---|---|---|---|---|---|
| :8881 | Atlasz Secure Server | TCP | Web Services | caution | 67.6k |
| :443 | HTTPS | TCPtls | Web Services | caution | 65.9k |
| :8291 | Winbox MikroTik Admin | TCP | Security | caution | 62.9k |
| :3268 | Microsoft Global Catalog (GC) | TCPUDP | Security | caution | 54.6k |
| :135 | Microsoft EPMAP | TCPUDP | Security | caution | 51.9k |
| :3128 | Squid Proxy HTTP | TCP | Web Services | caution | 45.8k |
| :8080 | HTTP Alternate | TCPtls | Web Services | caution | 44.9k |
| :7000 | Vuze HTTPS Tracker | TCPtls | Security | caution | 28.9k |
risk mix of the 8 listed
- caution100%
3 of 8 encrypted