The first step to security is usually a firewall between the client and the host server, requiring the remote user to establish an authenticated connection with the firewall. Encryption is also an important component of a secure VPN. Encryption works by having all data sent from one computer encrypted in such a way that only the computer it is sending to can decrypt the data.
A firewall uses packet filtering to allow or disallow the flow of specific types of network traffic. IP packet filtering provides a way for administrators to define precisely what IP traffic is allowed to cross the firewall. IP packet filtering is important when private intranets are connected to public networks, such as the Internet. There are two approaches to using a firewall with a VPN server:
No company came closer to being a pick than ExpressVPN. It has a huge server network that performed well in our tests, plus easy-to-use applications on tons of platforms, and strong security technologies in place. A representative answered all our questions about company operations at length—except one. As noted in a PCWorld review of the service, ExpressVPN chooses not to disclose the company’s leadership or ownership. The company representative told us that this policy enabled ExpressVPN to build a private and secure product without compromise. “We think that this approach has been effective until now and that coupled with a stellar VPN product, we have succeeded in gaining a solid reputation in our industry. We are fortunate to be trusted by the many users worldwide who choose ExpressVPN.”
Google’s Android is the largest installed base with over 73% market share and more than a billion daily active users – so it’s no surprise that there are a large number of VPN apps that support the OS. Surprisingly the Android is one of the most vulnerable OS with 343 new malware samples used to found every hour last year; the number could have progressed. Hold your breath guys! There are 700,000 malicious apps on your Google Play Store and there’s a possibility that you’re using one of them.
When we tested other aspects of IVPN’s performance, it also satisfied our requirements. On the default settings, our real IP address didn’t leak out via DNS requests or IPv6 routing, let alone a standard IP address checker. The DNS-requests check indicated that the app was using the company’s internal DNS servers and that they were correctly configured. None of the 12 services we tested disclosed our true IP address (though some showed mismatched IPs). Every VPN we considered had to operate its own DNS servers in-house and not rely on ISP servers or public options like Google’s, which give third parties a chance to log or analyze the sites you visit. IVPN currently disables all IPv6 connectivity, though the company is looking at solutions to securely support it soon. Most companies we considered do the same; OVPN was the only company to support IPv6 addresses at the time of our testing.
My recommendation, and the protocol I most often choose to use, is OpenVPN. OpenVPN is a non-proprietary, open-source implementation of a VPN communication layer protocol. It's well-understood, well-regarded, generally quite secure, and robust. In addition, it has the benefit of being able to communicate over port 443, which is the standard port for https communication, which means almost all firewalls will allow OpenVPN traffic -- and most won't even be able to detect that a VPN is being used.
VPN services, while tremendously helpful, are not foolproof. There's no magic bullet (or magic armor) when it comes to security. A determined adversary can almost always breach your defenses in one way or another. Using a VPN can't help if you unwisely download ransomware on a visit to the Dark Web, or if you foolishly give up your data to a phishing attack.