Virtual Private Networks (VPNs) allow private use of a public network. They enable mobile computers and other devices to connect to a company’s private network by creating an encrypted tunnel from the network that’s owned by the company, over the Internet and to the remote device on the other end. The most commonly used technologies to do this are Secure Sockets Layer (SSL) and IP Security (IPSec). These effectively extend the company’s network, creating a Virtual Private Network.
The costs tend to be lower than other kinds of remote access and the concept, from a network administration standpoint is simple. However, VPNs open up a couple of vulnerabilities that must be addressed. That device must be given the same level of protection as those inside the company doors or viruses can infect the corporate network. Secondly, when the physical security of the home office is not available; anyone may be able to pick up that device and try to use it. Extra care must be taken to authenticate the person who is using that device to connect to the network.