Virtual private network

Best VPN Services

How VPNs Work
A VPN is created by establishing a virtual point-to-point connection through the use of dedicated connections, virtual tunneling protocols , or traffic encryption. Cisco Press, , p. But since most router implementations support a software-defined tunnel interface, customer-provisioned VPNs often are simply defined tunnels running conventional routing protocols. If either fails, the connection fails. This article is in a list format that may be better presented using prose.

How it Works

How Does a VPN Work?

It may support IPv4 or IPv6. This section discusses the main architectures for PPVPNs, one where the PE disambiguates duplicate addresses in a single routing instance, and the other, virtual router, in which the PE contains a virtual router instance per VPN. The former approach, and its variants, have gained the most attention. RDs disambiguate otherwise duplicate addresses in the same PE.

By the provisioning of logically independent routing domains, the customer operating a VPN is completely responsible for the address space. 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. Trusted VPNs do not use cryptographic tunneling, and instead rely on the security of a single provider's network to protect the traffic. From the security standpoint, VPNs either trust the underlying delivery network, or must enforce security with mechanisms in the VPN itself.

Unless the trusted delivery network runs among physically secure sites only, both trusted and secure models need an authentication mechanism for users to gain access to the VPN. Users utilize mobile virtual private networks in settings where an endpoint of the VPN is not fixed to a single IP address , but instead roams across various networks such as data networks from cellular carriers or between multiple Wi-Fi access points.

Increasingly, mobile professionals who need reliable connections are adopting mobile VPNs. A conventional VPN can not withstand such events because the network tunnel is disrupted, causing applications to disconnect, time out, [30] or fail, or even cause the computing device itself to crash.

Instead of logically tying the endpoint of the network tunnel to the physical IP address, each tunnel is bound to a permanently associated IP address at the device. The mobile VPN software handles the necessary network-authentication and maintains the network sessions in a manner transparent to the application and to the user.

With HIP a mobile host maintains its logical connections established via the host identity identifier while associating with different IP addresses when roaming between access networks.

With the increasing use of VPNs, many have started deploying VPN connectivity on routers for additional security and encryption of data transmission by using various cryptographic techniques. Supported devices are not restricted to those capable of running a VPN client. Many router manufacturers supply routers with built-in VPN clients. Setting up VPN services on a router requires a deep knowledge of network security and careful installation.

Minor misconfiguration of VPN connections can leave the network vulnerable. Performance will vary depending on the ISP. One major limitation of traditional VPNs is that they are point-to-point, and do not tend to support or connect broadcast domains.

Therefore, communication, software, and networking, which are based on layer 2 and broadcast packets , such as NetBIOS used in Windows networking , may not be fully supported or work exactly as they would on a real LAN.

A VPN connection may not be as robust as a direct connection to a network. If either fails, the connection fails. From Wikipedia, the free encyclopedia. For other uses, see VPN disambiguation. This article is in a list format that may be better presented using prose.

You can help by converting this article to prose, if appropriate. Editing help is available. This section needs additional citations for verification.

Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. August Learn how and when to remove this template message. Cisco Secure Virtual Private Network.

Internet working Technologies Handbook, Third Edition. Cisco Press, , p. Digital Subscriber Line Engineering Consortium, , p. Archived from the original on 15 June It just happens to interoperate with their equipment. Comparing, designing, and deploying VPNs 1st print. Retrieved 29 August Generic Routing Encapsulation over IPv4 networks. Networking Technology Series 4 ed. Closing the Gap" , SearchMobileComputing. In addition, traveling employees like salespeople need an equally secure and reliable way to connect to their business's computer network from remote locations.

One popular technology to accomplish these goals is a VPN virtual private network. A VPN is a private network that uses a public network usually the Internet to connect remote sites or users together.

The VPN uses "virtual" connections routed through the Internet from the business's private network to the remote site or employee. By using a VPN, businesses ensure security -- anyone intercepting the encrypted data can't read it. VPN was not the first technology to make remote connections. Several years ago, the most common way to connect computers between multiple offices was by using a leased line. Leased lines, such as ISDN integrated services digital network, Kbps , are private network connections that a telecommunications company could lease to its customers.

Leased lines provided a company with a way to expand its private network beyond its immediate geographic area. These connections form a single wide-area network WAN for the business. Though leased lines are reliable and secure, the leases are expensive, with costs rising as the distance between offices increases. Today, the Internet is more accessible than ever before, and Internet service providers ISPs continue to develop faster and more reliable services at lower costs than leased lines.

To take advantage of this, most businesses have replaced leased lines with new technologies that use Internet connections without sacrificing performance and security. Businesses started by establishing intranets , which are private internal networks designed for use only by company employees.

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