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.
There is a PPTP control connection between the IP address of the PPTP client using a dynamically allocated TCP port and the IP address of the PPTP server using the reserved TCP port 1723. The PPTP control connection carries the PPTP call control and management messages that are used to maintain the PPTP tunnel. This includes the transmission of periodic PPTP Echo-Request and PPTP Echo-Reply messages to detect a connectivity failure between the PPTP client and PPTP server. PPTP control connection packets consist of an IP header, a TCP header, a PPTP control message, and a data-link trailer and header as shown in the following figure:
Unlike the separate tunnels created for each voluntary client, multiple dial-up clients can share a tunnel between the FEP and the tunnel server. When a second client dials into the access server (FEP) to reach a destination for which a tunnel already exists, there is no need to create a new instance of the tunnel between the FEP and tunnel server. Instead, the data traffic for the new client is carried over the existing tunnel. Since there can be multiple clients in a single tunnel, the tunnel is not terminated until the last user of the tunnel disconnects.
Corporate and Exit Locations: Depending on what you’re using a VPN for, your service’s location—and the exit locations you can choose—are important to consider. If you want to get around a location restriction and watch live TV in the UK, for example, you want to make sure your VPN service provider has servers in the UK. If you’re concerned about privacy or state-sponsored snooping, you may want to pick a service operated outside of your home country. Similarly, if the service is based on the US, they’re subject to US laws, and may be forced to turn over usage data to the authorities upon request. Many people make more of this than they should (we’ve seen overseas services turn over their data to friendly governments without any hesitation repeatedly), but it’s important to make sure a VPN has servers in multiple locations—or at least the location you’re interested in—when shopping.
Like most well-known VPN companies, IVPN supports a variety of privacy groups and causes. Pestell told us he worked with the Center for Democracy & Technology to improve trust in VPNs with a handful of transparency initiatives before they were announced. Neena Kapur of The New York Times (parent company of Wirecutter) information security team noted that IVPN’s leadership transparency and its relationship with CDT were significant pluses that contributed to its trustworthiness. Pestell was also the only representative we spoke with to offer to arrange for one of our experts to audit the company’s server and no-logging policies.1 We cover trust issues with VPNs at length elsewhere in this guide, but we believe that IVPN takes an active role in protecting its customers’ privacy and is not a dude wearing a dolphin onesie.
AVG Secure VPN Virtual Private Network (VPN) gives you a secure and private connection to unrestricted internet access. It does that by encrypting your connection so nobody can snoop on your online activity. The result? Secure and private access to any site — anywhere, anytime. That’s your favourite sites, shows and subscription services all with uncensored access.

There's a reason why all these VPNs are paid. Providing encryption and VPN services to millions of users is a resource-intensive work that requires servers across the world. A free VPN might be enough for something minor like checking foreign news occasionally. If you need a VPN on a regular basis, however, you’re better off with a reliable paid service.
Most VPN providers don’t give you the option, anyway, but don’t disable encryption altogether. Additionally, 128-bit AES is the minimum strength encryption necessary for a VPN to do its job and keep your data safe. It’s effectively un-crackable and is slightly faster than 256-bit AES, which is also common. A handful of VPNs use Blowfish encryption, which tends to be slower than its AES counterpart. We recommend at least 448-bit Blowfish encryption if you go that route.

It's not just the bad guys who are watching your traffic. Congress, for example, has granted internet service providers the right to sell anonymized metadata about your activities online. That's unfortunate, for a number of reasons. Fortunately, a VPN makes it much harder for even your ISP to monitor your activity and helps keep your privacy in your hands.
Anti-Malware/Anti-Spyware Features: Using a VPN doesn’t mean you’re invulnerable. You should still make sure you’re using HTTPS whenever possible, and you should still be careful about what you download. Some VPN service providers—especially mobile ones—bundle their clients with anti-malware scanners to make sure you’re not downloading viruses or trojans. When you’re shopping, see if the providers you’re interested in offer anti-malware protection while you’re connected. For example, previously mentioned Hotspot Shield offers malware protection to its premium users. It may not be a dealbreaker for you, but it’s always good to have someone watching your back.
Before anything else, understand that if you want to use a VPN you should be paying for it. Free VPNs are either selling your browsing data in aggregated form to researchers and marketers, or giving you a paltry amount of data transfer every month. Either way, a basic rule of thumb is that a free VPN will not protect your privacy in any meaningful way.

We believe privacy and security are fundamental human rights, so we also provide a free version of ProtonVPN to the public. Unlike other free VPNs, there are no catches. We don't serve ads or secretly sell your browsing history. ProtonVPN Free is subsidized by ProtonVPN paid users. If you would like to support online privacy, please consider upgrading to a paid plan for faster speeds and more features.


Are you so used to your data traveling over Wi-Fi that you've stopped worrying about the security of that data—and about who else might be spying on it, or even stealing it for nefarious purposes? If so, you are—sadly—in the majority, and you ought to consider using a viritual private network, or VPN. In fact, when PCMag conducted a survey on VPN usage, we found that a dismal 71 percent of the 1,000 respondents had never used a VPN. Even among those who support net neutrality—who you might think would tend to be well informed on technology and privacy issues—only 45 percent had used a VPN.
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