Frequently Asked Questions VPN & Remote Networking
What is a VPN?
A VPN, or Virtual Private Network, is a network that uses the Internet for corporate data communication. Because access to the Internet is so cheap, a VPN provides a low-cost method of linking offices together and providing remote users with access to the corporate network. VPNs are particularly attractive for companies with international offices, since the cost savings can be enormous. Within the UK, the roll-out of ADSL means that even the smallest companies can now implement VPNs for affordable, high speed inter-office links and for remote users.
How does it work?
In the case of a VPN linking several offices together, each office will have its own VPN device. Each device encrypts network data destined for one of the other offices, and then sends it through the Internet to a corresponding device in the other office. This second VPN device in turn decrypts the data it has received, and sends it on to the office network just like normal data. In the case of remote users, VPN client software on their desktops, laptops and PDAs does the encryption before sending the data out to the Internet.
What sort of Internet connection do my offices need to access a VPN?
Offices linked together with a VPN normally have leased line or ADSL connections to the Internet. In fact any kind of connection to the Internet can be used, but modem- and ISDN-based connections tend to be too slow and too expensive to use.
What sort of Internet connection do remote users need to access a VPN?
Remote users can have any kind of connection to the Internet: modem, ISDN, ADSL, leased line, mobile phone, wireless – if they can get to the Internet, they can use a VPN.
How safe is data sent through a VPN?
To all intents and purposes, and assuming that things have been set up correctly, VPN data is perfectly safe when it is travelling through the Internet. VPN data is encrypted using triple-DES encryption, which has never been broken. This means that nobody can read the data whilst in transit. Secondly, VPN devices are capable of telling if data has been tampered with, in which case it is discarded. In the case of remote users, we normally supply strong authentication devices that ensure only authorised users can access the VPN, even if a laptop has been lost or stolen. The combination of encryption and authentication means that for the vast majority of commercial organizations, VPNs are safe.
What applications can I run through a VPN?
VPNs support pretty much anything that currently runs on a network. In other words, whatever applications you are currently using can almost certainly be deployed through a VPN to remote offices on the other side of the world, or to remote users. By combining VPNs with thin client technology you can access your network applications from a handheld PDA, even whilst travelling.
Will I need to make changes to my existing applications?
In most cases your applications won’t even realise they are going through a VPN. In a very small number of cases we may need to adjust some settings in order to get the best performance from a VPN, but usually the only changes that need to be made are to your routers, to redirect data through the VPN.
Can I run telephone calls through a VPN?
Yes, depending on the type of telephone system you have installed.
What is thin client technology?
Thin client is a way of providing access to applications, either to remote offices or to remote users, in a way that provides acceptable performance over remote links. Applications that work happily within a normal network may be painfully slow or not work at all over remote links, where the connection speed can be several thousand times slower than on the local network. With thin client, a special server on your network runs applications on behalf of remote users so that the applications are actually running on the fast local network. The only data that travels across the slower remote links consists of screen updates sent from the thin client server to the remote users, and keyboard and mouse inputs from the remote user to the thin client server. By combining VPNs with thin client technology you can deploy your applications to remote users or remote offices anywhere in the world, cheaply and securely. You can even deploy applications to remote users that have nothing but a Web browser.
So is thin client only useful for remote users?
Not at all – thin client offers a number of significant benefits even if you have a single office and no remote users. Since your applications are actually installed and running on the thin client server, and not on the individual PCs, managing them becomes vastly simpler. If you need to update your application software you only have to do it once – on the thin client server. If you need to deploy a new application to all your users, you only have to install it once – on the thin client server. The benefits are obvious. Another advantage of using thin client is that you no longer have to keep upgrading your PCs to keep up with new applications; the only software the PCs need is the thin client software, or simply a web browser – and you can use virtually any old PC for that.