Virtual LAN (VLAN) is a Layer 2 technique that allow for the coexistence of multiple local area network (LAN) broadcast domains, interconnected via trunks using the IEEE 802.1Q trunking protocol. Other trunking protocols have been used but have become obsolete, including Inter-Switch Link (ISL), IEEE 802.10 (originally a security protocol but a subset was introduced for trunking), and ATM LAN Emulation (LANE).
This could be bad. I'm not terribly concerned if Comcast discovers my secret passion for muscle cars and I get more ads for car customizing kits. It might be annoying, but I'm not doing anything I really want to hide. Where the problem could occur is if ISPs start inserting their own ads in place of ads by, say, ZDNet. That could cut off the revenue that keeps websites alive, and that could have very serious repercussions.

Wi-Fi attacks, on the other hand, are probably far more common than we'd like to believe. While attending the Black Hat convention, researchers saw thousands of devices connecting to a rogue access point. It had been configured to mimic networks that victim's devices had previously connected to, since many devices will automatically reconnect to a known network without checking with the user. That's why we recommend getting a VPN app for your mobile device to protect all your mobile communications. Even if you don't have it on all the time, using a mobile VPN is a smart way to protect your personal information.
SSTP (Secure Socket Tunneling Protocol) is a suitable alternative to standard protocols in areas where VPNs are restricted because it can bypass most firewalls. SSTP is quite similar to OpenVPN but, unlike OpenVPN, it is owned by Microsoft, which means it is not available for independent auditing. Microsoft’s history of cooperating with the NSA does not inspire confidence in this standard.
Because it is impossible to update separate user accounts on separate servers for the same user simultaneously, most administrators set up a master account database at a domain controller or on a RADIUS server. This enables the VPN server to send the authentication credentials to a central authenticating device, and the same user account can be used for both dial-up remote access and VPN-based remote access.

A remote-access VPN uses public infrastructure like the internet to provide remote users secure access to their network. This is particularly important for organizations and their corporate networks. It's crucial when employees connect to a public hotspot and use the internet for sending work-related emails. A VPN client, on the user's computer or mobile device connects to a VPN gateway on the company's network. This gateway will typically require the device to authenticate its identity. It will then create a network link back to the device that allows it to reach internal network resources such as file servers, printers and intranets, as if it were on the same local network.
If a VPN client that uses a PPTP connection is behind a NAT, the NAT must include a NAT editor that can translate PPTP traffic. The NAT editor is required because tunneled PPTP data has a GRE header rather than a TCP header or a UDP header. The NAT editor uses the Call ID field in the GRE header to identify the PPTP data stream and translate IP addresses and call IDs for PPTP data packets that are forwarded between a private network and the Internet.
From a feature-to-dollar standpoint, TunnelBear’s premium offering doesn’t beat out our two previous recommendations. StrongVPN and SurfEasy are better bets if you’re willing to pay. But, TunnelBear does offer a free tier, doesn’t maintain logs, and it is extremely easy to get up and running with their dead-simple apps for desktop and mobile users alike.
PureVPN has servers in more than 140 countries and can be very inexpensive if you pay for two years up front. It also lets you "split-tunnel" your service so that some data is encrypted and other data isn't. But PureVPN was at or near the back of the pack in almost all of our 2017 performance tests. In October 2017, the U.S. Department of Justice disclosed in a criminal complaint that PureVPN had given the FBI customer logs in reference to a cyberstalking case, which kind of negates the entire point of using a VPN.
IPSec – Internet Protocol Security (IPSec) can be utilized with Layer 2 Tunneling Protocol (L2TP) or Internet Key Exchange version 2 (IKEv2). While it is not open source, it does do well in the performance category and can be used natively (without apps) on most operating systems. IPSec/IKEv2 may be the best protocol to use with some mobile devices (iOS), which do not work as well with OpenVPN.

Latency is a measurement of time between when your computer sends a request and when it receives a response. It's often called ping time. Lots of things can affect latency; the distance your request physically travels through fiber has a big impact, for example. Latency is measured in milliseconds, however, so even a large increase may not be noticeable to the average user. Latency is very important when playing video games over a VPN, as lower latency means a more responsive experience with less lag.

Many VPN services also provide their own DNS resolution system. Think of DNS as a phone book that turns a text-based URL like "" into a numeric IP address that computers can understand. Savvy snoops can monitor DNS requests and track your movements online. Greedy attackers can also use DNS poisoning to direct you to bogus phishing pages designed to steal your data. When you use a VPN's DNS system, it's another layer of protection.