pptpsetup

--create interface
    Required. Specifies that a new PPTP connection should be created with the given interface name (e.g., vpn0).

--delete interface
    Required. Deletes the configuration files for the specified PPTP interface.

--start interface
    Starts the PPTP connection associated with the specified interface.

--stop interface
    Stops the PPTP connection associated with the specified interface.

--status interface
    Displays the current status of the specified PPTP connection.

--server server_ip
    Required with --create. The IP address or hostname of the PPTP server.

--username username
    Required with --create. The username for authentication with the PPTP server.

--password password
    Required with --create. The password for authentication with the PPTP server.

--encrypt
    Enables MPPE (Microsoft Point-to-Point Encryption) encryption. This is highly recommended for security.

--mppe-stateful
    Enables stateful MPPE encryption. This is sometimes required for compatibility with certain PPTP servers.

--local-ip local_ip
    Specifies the local IP address for the PPTP interface. Normally, the PPTP server assigns one.

--no-default-route
    Prevents pptpsetup from adding a default route via the PPTP connection. Useful if you only want specific routes through the VPN.

--no-dns
    Prevents pptpsetup from setting DNS servers provided by the PPTP server. Useful if you want to use your existing DNS configuration.

--set-option option
    Passes an additional option directly to pppd. Can be used multiple times for different options.

--log logfile
    Specifies a file to log pppd output, which can be helpful for debugging connection issues.

--debug
    Enables verbose debugging output for pppd.

--force-hostname hostname
    Forces pppd to use a specific hostname during authentication, which might be required by some PPTP servers.

--chap-secrets-file file
    Specifies an alternative chap-secrets file to use instead of the default.

--options-file file
    Specifies an alternative options file for the PPTP connection.

--peers-file file
    Specifies an alternative peers file for the PPTP connection.

--version
    Displays the pptpsetup version information.

--help
    Displays the help message and exits.

pptpsetup is a utility program designed to simplify the configuration of a Point-to-Point Tunneling Protocol (PPTP) client connection on Linux systems. It acts as a wrapper around the pppd (PPP daemon) and ip commands, automating the creation of necessary configuration files located primarily in /etc/ppp/. These files include secrets for authentication (e.g., chap-secrets), options for the PPTP connection, and peer configuration files.

The command allows users to specify the PPTP server address, VPN username, password, and optionally a local IP address and routing information. By automating these steps, pptpsetup reduces the manual effort and potential for errors when setting up a PPTP VPN, making it more accessible for users who need to connect to PPTP-based VPNs, typically in older network environments or specific corporate setups. It's important to note that while pptpsetup facilitates connection, PPTP itself is an outdated and generally insecure protocol.

• Security Risk: PPTP is an outdated and insecure VPN protocol with known vulnerabilities, particularly regarding its authentication (MS-CHAPv2) and encryption (MPPE). It is susceptible to various attacks, including dictionary attacks and bit-flipping attacks on encrypted data.
  Usage is strongly discouraged for sensitive data or over untrusted networks. Newer, more secure VPN protocols like OpenVPN or IPsec (IKEv2) should be preferred.
• Root Privileges: pptpsetup modifies system network configuration files and requires root privileges to run successfully.
• Dependencies: It relies on the pppd (PPP daemon) and ip utilities being installed and correctly configured on the system.
• Configuration Overrides: While pptpsetup simplifies setup, advanced pppd configurations might require manual editing of the generated files.

When a connection is created with --create, pptpsetup generates several configuration files, typically in /etc/ppp/:

• /etc/ppp/chap-secrets: Contains the username and password for authentication.
• /etc/ppp/options.pptpsetup.interface: Specific options for the pppd instance related to the PPTP connection.
• /etc/ppp/peers/interface: Defines the peer (PPTP server) information and links to the options file.

These files can be manually inspected or modified for advanced configurations.

By default, pptpsetup attempts to set the newly established PPTP connection as the default route for all internet traffic. This means all your network traffic will flow through the VPN tunnel. If you only want specific traffic to go through the VPN, use the --no-default-route option and manually configure specific routes using the ip route command.

pptpsetup is part of the pptp-client project, which aimed to provide a functional PPTP client for Linux. Its development emerged from the need for Linux users to connect to Microsoft Windows-based VPN servers that predominantly used PPTP in the late 1990s and early 2000s.

While initially useful for interoperability, the underlying PPTP protocol quickly showed its cryptographic weaknesses. Although pptpsetup continued to be maintained for compatibility purposes, its usage has declined significantly in favor of more robust and secure VPN solutions. Its primary historical significance lies in simplifying an otherwise complex manual configuration process for a then-common VPN standard.

pppd(8), ip(8), route(8), ifconfig(8), openvpn(8), strongswan(8)