DSL and Networks Information

Mobile VPNs are VPNs designed for mobile and wireless users. They integrate standards-based authentication and encryption technologies to secure data transmissions to and from devices and to protect networks from unauthorized users. Designed for wireless environments, Mobile VPNs are designed as an access solution for users that are on the move and require secure access to information and applications over a variety of wired and wireless networks. Mobile VPNs allow users to roam seamlessly across IP-based networks and in and out of wireless coverage areas without losing application sessions or dropping the secure VPN session. For instance, highway patrol officers require access to mission-critical applications in order to perform their jobs as they travel across different subnets of a mobile network, much as a cellular radio has to hand off its link to repeaters at different cell towers.

Secure VPNs use cryptographic tunneling protocols to provide the intended confidentiality (blocking snooping and thus Packet sniffing), sender authentication (blocking identity spoofing), and message integrity (blocking message alteration) to achieve privacy. When properly chosen, implemented, and used, such techniques can provide secure communications over unsecured networks.

Secure VPN protocols include the following:

* IPsec (IP security) - commonly used over IPv4, and an obligatory part of IPv6.
* SSL/TLS used either for tunneling the entire network stack, as in the OpenVPN project, or for securing what is, essentially, a web proxy. SSL is a framework more often associated with e-commerce, but it has been built-upon by a number of vendors to provide remote access VPN capabilities. A major practical advantage of an SSL-based VPN is that it can be accessed from the locations that restrict external access to SSL-based e-commerce websites only, thereby preventing VPN connectivity using IPsec protocols. SSL-based VPNs are vulnerable to trivial Denial of Service attacks mounted against their TCP connections because latter are inherently unauthenticated.
* OpenVPN, an open standard VPN. It is a variation of SSL-based VPN that is capable of running over UDP. Clients and servers are available for all major operating systems.
* L2TPv3 (Layer 2 Tunneling Protocol version 3), a new release.
* VPN Quarantine The client machine at the end of a VPN could be a threat and a source of attack; this has no connection with VPN design and is usually left to system administration efforts. There are solutions that provide VPN Quarantine services which run end point checks on the remote client while the client is kept in a quarantine zone until healthy. Microsoft ISA Server 2004/2006 together with VPN-Q 2006 from Winfrasoft or an application called QSS (Quarantine Security Suite) provide this functionality.
* MPVPN (Multi Path Virtual Private Network). MPVPN is a registered trademark owned by Ragula Systems Development Company. See Trademark Applications and Registrations Retrieval (TARR)

Trusted VPNs (sometimes referred to APNs - Actual Private Networks) do not use cryptographic tunneling, and instead rely on the security of a single provider’s network to protect the traffic. In a sense, these are an elaboration of traditional network and system administration work.

* Multi-Protocol Label Switching (MPLS) is often used to overlay VPNs, often with quality of service control over a trusted delivery network.
* Layer 2 Tunneling Protocol (L2TP) which is a standards-based replacement, and a compromise taking the good features from each, for two proprietary VPN protocols: Cisco’s Layer 2 Forwarding (L2F) (now obsolete) and Microsoft’s Point-to-Point Tunneling Protocol (PPTP) .

The Internet Engineering Task Force (IETF) categorized a variety of VPNs, some of which, such as Virtual LANs (VLAN) are the standardization responsibility of other organizations, such as the Institute of Electrical and Electronics Engineers (IEEE) Project 802, Workgroup 802.1 (architecture). Originally, network nodes within a single enterprise were interconnected with Wide Area Network (WAN) links from a telecommunications service provider. With the advent of LANs, enterprises could interconnect their nodes with links that they owned. While the original WANs used dedicated lines and layer 2 multiplexed services such as Frame Relay, IP-based layer 3 networks, such as the ARPANET, Internet, military IP networks (NIPRNET,SIPRNET,JWICS, etc.), became common interconnection media. VPNs began to be defined over IP networks . The military networks may themselves be implemented as VPNs on common transmission equipment, but with separate encryption and perhaps routers.

It became useful first to distinguish among different kinds of IP VPN based on the administrative relationships, not the technology, interconnecting the nodes. Once the relationships were defined, different technologies could be used, depending on requirements such as security and quality of service.

When an enterprise interconnected a set of nodes, all under its administrative control, through an LAN network, that was termed an Intranet . When the interconnected nodes were under multiple administrative authorities, but were hidden from the public Internet, the resulting set of nodes was called an extranet. Both intranets and extranets could be managed by a user organization, or the service could be obtained as a contracted offering, usually customized, from an IP service provider. In the latter case, the user organization contracted for layer 3 services much as it had contracted for layer 1 services such as dedicated lines, or multiplexed layer 2 services such as frame relay.

The IETF distinguishes between provider-provisioned and customer-provisioned VPNs . Much as conventional WAN services can be provided by an interconnected set of providers, provider-provisioned VPNs (PPVPNs) can be provided by a single service provider that presents a common point of contact to the user organization.

Attractions of VPNs to enterprises include:

* Shared facilities may be cheaper—especially in capital expenditure (CAPEX)—than traditional routed networks over dedicated facilities.
* Can rapidly link enterprise offices, as well as small-and-home-office and mobile workers.
* Allow customization of security and quality of service as needed for specific applications.
* Can scale to meet sudden demands, especially when provider-provisioned on shared infrastructure.
* Can reduce operational expenditure (OPEX) by outsourcing support and facilities.

Distributing VPNs to homes, telecommuters, and small offices may put access to sensitive information in facilities not as well protected as more traditional facilities. VPNs need to be designed and operated under well-thought-out security policies. Organizations using them must have clear security rules supported by top management. When access goes beyond traditional office facilities, where there may be no professional administrators, security must be maintained as transparently as possible to end users.

Some organizations with especially sensitive data, such as health care companies, even arrange for an employee’s home to have two separate WAN connections: one for working on that employer’s sensitive data and one for all other uses.More common is that bringing up the secure VPN cuts off Internet connectivity for any use except secure communications into the enterprise; Internet access is still possible but will go through enterprise access rather than that of the local user.

In situations in which a company or individual has legal obligations to keep information confidential, there may be legal problems, even criminal ones, as a result. Two examples are the HIPAA regulations in the U.S. with regard to health data, and the more general European Union data privacy regulations which apply to even marketing and billing information and extend to those who share that data elsewhere.