HP 635n Practical IPsec Deployment for Printing and Imaging Devices - Page 7

Figure 4 - Internet Age Here we have a diagram that is actually pretty familiar to most people - assume that the Remote Router is a cable modem and the Remote Office is really your home. More than likely, you are attaching to the Internet via an Internet Service Provider or ISP. In this example, we are going to use the power of the public Internet to provide connectivity between the Corporate Office and the Remote Office. Wow - This connectivity is great! No more leased lines! Connecting to offices together is as simple as having an Internet connection. As luck would have it, the head of Finance at the Remote Office and the company's CEO resides at the Corporate Office. Imagine the emails that go between these two individuals over the public Internet in the clear! Would you shout your 401(k) account password across a crowded room to your spouse? Of course not, yet that is exactly what is happening in Figure 4, except it involves electronic data rather than sound waves. How can we solve this problem when leased lines aren't an option any more? We need a way to provide private communication over a public network. In short, we need a Virtual Private Network to be formed over the Internet. Here, IPsec comes to the rescue. Refer to Figure 5 - Internet VPN Age 7