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).

For two years running, Private Internet Access has performed the best in our network tests and remained the cheapest full-fledged VPN service we've tried. It has more than 3,000 servers worldwide, supports platforms ranging from Windows and Mac to open-source routers, and lets you customize your tunneling and encryption protocols. You can pay in bitcoin, and you don't have to provide your real name.
In some organization intranets, the data of a department, such as human resources, is so sensitive that the network segment of the department is physically disconnected from the rest of the intranet. While this protects the data of the human resources department, it creates information accessibility problems for authorized users not physically connected to the separate network segment.
MS-CHAP version 2 (MS-CHAP v2) is an updated encrypted authentication mechanism that provides stronger security for the exchange of user name and password credentials and determination of encryption keys. With MS-CHAP v2, the NAS sends a challenge to the client that consists of a session identifier and an arbitrary challenge string. The remote access client sends a response that contains the user name, an arbitrary peer challenge string, and an encrypted form of the received challenge string, the peer challenge string, the session identifier, and the user's password. The NAS checks the response from the client and sends back a response containing an indication of the success or failure of the connection attempt and an authenticated response based on the sent challenge string, the peer challenge string, the encrypted response of the client, and the user's password. The remote access client verifies the authentication response and, if correct, uses the connection. If the authentication response is not correct, the remote access client terminates the connection.
Some VPNs offer “split tunneling,” which routes all traffic through your VPN except specific services or sites that you allow. For example, you might want to send your Web traffic through your VPN but stream Netflix on your fast, domestic connection. But these types of rules are complicated to implement without also leaking other important information, and we didn’t assess how effective they were in practice.
The bad news for anyone used to free services is that it pays to pay when it comes to a VPN. There are tons of free options from reputable companies, but these are usually a poor substitute for the paid options. Free services usually allow a limited amount of bandwidth usage per month or offer a slower service. Tunnel Bear, for example, offers just 500MB of free bandwidth per month, while CyberGhost offers a free service that is significantly slower than its paid service.
Torrenting/P2P support – Getting torrents to work with PIA is no problem. You can easily gain access to P2P sites and clients with PIA if they are blocked in your region. As with IPVanish, however, PIA complies with the DMCA (Digital Millennium Copyright Act) which protects the copyrights of content creators. Therefore, PIA should be avoided if you are looking for a safe to torrent.
When you download a file from a server without a VPN, there’s a chance you will encounter network congestion, most likely on your nearby ISP network or at the download server itself. When you use a VPN service, you add a third potential bottleneck to the route. Whether because of server load or congestion on the network surrounding the server, there’s a higher chance that your speed will be affected while connected to a VPN.
Opera VPN works only through the Opera web browser, and it shouldn't be used for sensitive communications. Once very fast, Opera's VPN connections were painfully slow in our most recent tests. The Opera VPN mobile apps, which were full-fledged VPN services that performed decently in our 2017 tests, unfortunately closed up shop at the end of April 2018.

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.
Add to that the volume of add-ons offered by TorGuard, especially access to a 10Gbit network and static IP addresses which aren't likely to be blocked, and it's a very competitive service. It also has greatly expanded its collection of servers and because it is so focused on serving BitTorrent, it's clear that the company cares about how fast data moves through its network.
A proxy server is another way to conceal your real location. By transferring data through a proxy server the data appears to be going to that server, not you - so for example if you’re in the US and the proxy is in Switzerland, the website or service will think it’s talking to a machine in Switzerland. The main difference is that VPNs protect all your traffic while proxies tend to be limited to specific types of data, such as peer to peer networking or web browsing. 
There are many things a VPN must do well to be useful, and one of the most important ones is to be fast. You can likely get around many other shortcomings. But if your VPN is slower than a dial-up modem (for those of us who remember them), there will be trouble ahead. Not only will you be less likely to use your VPN, but you will probably also curse it every time you do. It’s money well wasted.
Aside from providing an exceptional VPN server for encrypting traffic, Speedify leverages all types of available internet connection to increase bandwidth, bolster internet speeds, and lower latency. This results in a smooth and reliable connection on any platform, whether using mobile devices or a desktop. This is achieved through its Channel Bonding functionality that combines all types of internet connections, including WiFI, VPN, 3G, and, 4G.

The service proudly states that it allows users to stream music or streaming video while connected to move between annoying content blocks, especially if you are away from home and live abroad but want to watch your favorite TV shows Play in your country or have a subscription to a streaming music service. There are more servers in more than 61 countries, and there were almost no losses in our tests, that is, performance first. With robust cryptography and a reliable network, now is the right time to check IPVanish’s 7-day trial offer.

We didn’t audit any VPN services ourselves (though IVPN, our top pick, offered to arrange such an exercise), but we did ask detailed questions about each service’s operations as a way to judge whether a company was acting in good faith. Good faith is important, because there aren’t many avenues to penalize a VPN company that isn’t following through on its promises. In the US, companies making false claims about their products are policed by the Federal Trade Commission, and to some extent state attorneys general. Joseph Jerome at CDT told us that companies violating their own privacy policy or claims about logging would be “a textbook example of a deceptive practice under state and federal consumer protection laws,” and in theory, “the FTC could seek an injunction barring the deceptive practice as well as potentially getting restitution or other monetary relief.”
You might be thinking: “I only need one connection, don’t I?” What if you want to set up VPN access on more than one device, for more than one family member, on your home router, or the like? You’ll need multiple concurrent connections to the service. Or, perhaps, if you’re particularly security oriented, you’d like to configure multiple devices to use multiple different exit nodes so your collective personal or household traffic isn’t all bundled together.
If your needs are more serious than watching Netflix or keeping some war kiddie at the coffee shop from snooping on your social media activity, a VPN may not be for you. Many VPNs promise anonymity, but few can actually provide it–and you’re still trusting the VPN provider with access to your traffic, which isn’t ideal. For that, you likely want something more like Tor, which–while not perfect–is a better anonymity solution than VPNs.
The service uses Advanced Encryption Standard with a 256-bit key, a common method employed by VPN services. Connections are protected using 2048-bit public key encryption. For privacy, the service offers a malware detection software. What is good about the software is that it can be downloaded and used without providing any personal information. This holds as long as you use the free version of the software and never contact customer support.
Opera VPN works only through the Opera web browser, and it shouldn't be used for sensitive communications. Once very fast, Opera's VPN connections were painfully slow in our most recent tests. The Opera VPN mobile apps, which were full-fledged VPN services that performed decently in our 2017 tests, unfortunately closed up shop at the end of April 2018.
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The main drawback is that maintains connection logs for network security, which they clearly explain on their website. These logs do not include any browsing or activity, but instead, just basic connection data and everything is erased daily. All support inquiries are handled internally by the network security professionals who run the service (no third-party support).

If the VPN client has a configured connection without a default route, the client adds a route that it infers from the Internet address class of the IP address assigned to it for the current connection. For a simple target network, such as a small office, this one route is sufficient to allow packets to be routed to the target network. However, for a complex network, administrators need to configure multiple routes to successfully direct packets to the remote network.

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.

You want to skip PPTP if at all possible. It’s a very dated protocol that uses weak encryption and due to security issues should be considered compromised. It might be good enough to secure your non-essential web browsing at a coffee shop (e.g. to keep the shopkeeper’s son from sniffing your passwords), but it’s not up to snuff for serious security. Although L2TP/IPsec is a significant improvements over PPTP, it lacks the speed and the open security audits found with OpenVPN.
VyprVPN offers the fastest VPN download for Windows, Mac, Android, iOS, TV and Router, enabling you to secure your desktop and mobile devices in seconds while receiving the fastest connection speeds around. Download the fastest VPN service with apps that are secure, easy-to-use and reliable. VyprVPN also includes time-saving features like one-click connect, one-tap server selection and a ping test to choose the fastest server.
The service’s no logs policy means that it does not store user online activity data and promises not to release them unless required by law, ensuring that your information is in safe hands. What sets this service apart from others is its refund policy. Users are able to use it for up to 10 hours or 10GB of bandwith and still get a refund, a far more generous policy than what others have to offer.
Finally, read the fine print to see if they restrict any protocols or services you wish to use the service for. If you want to use the service for file sharing, read the fine print to ensure your file sharing service isn’t blocked. Again, while it was typical to see VPN providers restrict services back in the day (in an effort to cut down on bandwidth and computing overhead) it’s more common today to find VPNs with an anything-goes policy.
If you are depending on your VPN to keep your activities even mildly anonymous, you need some sense of security that the VPN isn’t just going to go down and dump all your traffic out into the regular internet. What you want is tool known as a “kill switch system”. Good VPN providers have a kill switch system in place such that if the VPN connection fails for any reason it automatically locks down the connection so that the computer doesn’t default to using the open and unsecured internet connection.
You can pay for a Windscribe subscription with bitcoin, and you don't even have to provide an email address. The service is based in Canada, which may appeal to users wary of U.S. authorities. The only feature lacking is a kill switch to stop all internet activity if the VPN connection is lost while in use, but Windscribe argues that its built-in firewall prevents data leakage.
One of the most popular VPN services in the market, HideMyAss has a myriad of features that are sure to attract anyone who wants online anonymity. It uses a variety of servers that work with any operating system or mobile device. Aside from PPTP and OpenVPN protocols, the service supports L2TP, which is more difficult to block. Ideal for getting around censorship and firewalls.
PPTP - PPTP has been around since the days of Windows 95. The main selling point of PPTP is that it can be simply setup on every major OS. In short, PPTP tunnels a point-to-point connection over the GRE protocol. Unfortunately, the security of the PPTP protocol has been called into question in recent years. It is still strong, but not the most secure.
With  multiple clients, rich with different features, it’s no wonder this VPN service handles more than 10 million users. It covers Microsoft’s and Apple’s operating systems, but also iOS and Android. The interface is not the best out there and could definitely use some work, but these disadvantages are easily overshadowed by the awesome features this VPN offers.
Thankfully, there's a workaround for this problem. Instead of using the VPN app from the company from which you've purchased a subscription, you can download the standalone OpenVPN app. Open it, and you can enter your subscription information from the VPN company you've decided to work with. The OpenVPN app will then connect to the VPN company's servers using our preferred protocol.
Some countries don't have the same protections for freedom of press, speech, and expression that most democratic countries have. In fact, some regimes resort to oppressive measures to monitor and take action against those they see as threats to the government. People who dare to stand up have to take extra precautions to protect their communications. Journalists and researchers also send messages containing data that some people may want to try very hard to intercept.

CyberGhost, Romanian-based VPN that stands out as a free service without any restrictions. While reviewing Cyberghost VPN we found that the service is transparent with no hidden agendas of keeping logs or information. The company offers 1319+ servers across 61 countries; isn’t the network is larger enough to fulfill all our streaming needs. The company has secured its position in the VPN industry recently, with its feature-rich yet easy-to-use software, AES 256-BIT Encryption protocols and offers seven simultaneous connection.
To send on a LAN or WAN link, the IP datagram is finally encapsulated with a header and trailer for the data-link layer technology of the outgoing physical interface. For example, when an IP datagram is sent on an Ethernet interface, the IP datagram is encapsulated with an Ethernet header and trailer. When an IP datagram is sent over a point-to-point WAN link such as an analog phone line or ISDN, the IP datagram is encapsulated with a PPP header and trailer.
It usually relies on either Internet Protocol Security (IPsec) or Secure Sockets Layer (SSL) to secure the connection. However, SSL VPNs can also be used to supply secure access to a single application, rather than an entire internal network. Some VPNs also provide Layer 2 access to the target network; these will require a tunneling protocol like PPTP (Point-to-Point Tunneling Protocol) or L2TP (Layer 2 Tunneling Protocol) running across the base IPsec connection.
Some virtual networks use tunneling protocols without encryption for protecting the privacy of data. While VPNs often do provide security, an unencrypted overlay network does not neatly fit within the secure or trusted categorization.[citation needed] For example, a tunnel set up between two hosts with Generic Routing Encapsulation (GRE) is a virtual private network, but neither secure nor trusted.[23][24]

Some VPN services provide a free trial, so take advantage of it. Make sure you are happy with what you signed up for, and take advantage of money-back guarantees if you're not. This is actually why we also recommend starting out with a short-term subscription—a week or a month—to really make sure you are happy. KeepSolid VPN Unlimited offers a one-week Vacation subscription, for example. Yes, you may get a discount by signing up for a year, but that's more money at stake should you realize the service doesn't meet your performance needs.