There’s no point to a VPN that interferes with or logs your traffic—your ISP already does that. Free VPNs, such as Facebook’s Onavo, explicitly gather traffic data to resell or use it for marketing. We looked carefully at the privacy policies and marketing claims for each company we considered. In some cases, companies we considered had sworn in court filings that requests for data were impossible to fulfill. In other cases, we asked companies about their internal security and privacy standards to gauge the trustworthiness of their statements on logging.
In this approach, the firewall must be configured with input and output filters on its Internet and perimeter network interfaces to allow the passing of tunnel maintenance traffic and tunneled data to the VPN server. Additional filters can allow the passing of traffic to Web servers, FTP servers, and other types of servers on the perimeter network. As an added layer of security, the VPN server should also be configured with PPTP or L2TP/IPSec packet filters on its perimeter network interface as described in “VPN Server in Front of a Firewall” in this section.
Microsoft Challenge Handshake Authentication Protocol (MS-CHAP) is an encrypted authentication mechanism very similar to CHAP. As in CHAP, the NAS sends a challenge, which consists of a session ID and an arbitrary challenge string, to the remote client. The remote client must return the user name and an encrypted form of the challenge string, the session ID, and the MD4-hashed password. This design, which uses the MD4 hash of the password, helps provides an additional level of security because it allows the server to store hashed passwords instead of clear-text passwords or passwords that are stored using reversible encryption. MS-CHAP also provides additional error codes, including a password-expired code, and additional encrypted client-server messages that permit users to change their passwords during the authentication process. In MS-CHAP, both the client and the NAS independently generate a common initial encryption key for subsequent data encryption by MPPE.
Providers can also log less-specific data about when or how often you connect to your VPN service. In some cases, these logs are a routine part of server or account management, and can be responsibly separated and scrubbed. In other cases, VPN providers take note of every connection and use that information to actively police individual customers. Though it’s reasonable for companies to protect their networks from abuse, it becomes a dealbreaker when companies keep extensive connection data for a longer period of time. Some VPN companies we spoke with explained how a log might note your current connection for authentication purposes, but that log is deleted as soon as you disconnect. This kind of “live log” isn’t a concern, and even those culled every few hours—or as long as the end of each day—shouldn’t be confused with logs of your traffic and online destinations.
Supported Client Software Android, Chrome, Firefox, iOS, Linux, macOS, Windows Android, Chrome, iOS, Linux, macOS, Windows Android, Chrome, iOS, macOS, Opera, Windows Android, iOS, Linux, macOS, Windows Android, ChromeOS, iOS, Linux, macOS, Windows Android, iOS, Linux, macOS, Windows Android, iOS, macOS, Windows Android, iOS, macOS, Windows Android, Chrome, Firefox, iOS, Linux, macOS, Windows Android, iOS, macOS, Windows