TCP 1723
Synopsis
- TCP port 1723 is used by the Point-to-Point Tunneling Protocol (PPTP) for VPN control connections (data goes via GRE protocol 47).
- Microsoft Windows Server RRAS PPTP VPN servers listen on 1723/TCP, and Windows clients connect to that port.
- Router platforms with built-in PPTP servers—such as MikroTik RouterOS, ASUSWRT, and many TP-Link/DrayTek SOHO routers—expose TCP 1723.
- NAS/firewall products including Synology VPN Server (PPTP), QNAP QVPN (PPTP), OpenWrt’s pptpd, and older pfSense releases use TCP 1723.
- Linux PPTP daemons like pptpd and accel-pptp use port 1723 when deployed on VPS or on-prem hosts.
- Some multi-protocol VPN suites (e.g., SoftEther VPN) offer an optional PPTP compatibility mode that listens on 1723/TCP.
- Remote access appliances from vendors like DrayTek Vigor and Zyxel provide PPTP servers that rely on port 1723.
- This port is commonly targeted because PPTP’s MS-CHAPv2 authentication is weak, enabling offline cracking of captured handshakes and widespread brute-force attacks.
Observed activity
Last 30 days
Detailed chart