tailieunhanh - 22.5. Virtual Private Networking

. Virtual Private Networking After reading the previous pages, you might assume that it's a piece of cake for business people to connect to their corporate networks across the Internet from wherever they happen to be: their homes | . Virtual Private Networking After reading the previous pages you might assume that it s a piece of cake for business people to connect to their corporate networks across the Internet from wherever they happen to be their homes hotel rooms or local Starbucks. But even though the steps on the preceding pages work fine if you re dialing into your home machine they ll probably fail miserably when you want to connect to a corporate network. There s one enormous obstacle in your way Internet security. The typical corporate network is guarded by a team of steely-eyed administrators for whom Job Number One is preventing access by unauthorized visitors. They perform this job primarily with the aid of a super-secure firewall that seals off the company s network from the Internet. So how can you tap into the network from the road One solution is to create a hole in the firewall for each authorized user software that permits incoming Internet traffic only from specified IP addresses like your Mac s. Unfortunately this setup isn t bulletproof security-wise. It s also a pain for administrators to manage. Another solution You could dial directly into the corporate network modem-to modem. That s plenty secure but it bypasses the Internet and therefore winds up being expensive. Want proof Try this simple test Make a call from the Tokyo Hilton to the Poughkeepsie Sheet Metal home office. Have a look at your hotel bill when you check out. Fortunately there s a third solution that s both secure and cheap the Virtual Private Networke or VPN. Running a VPN allows you to create a super-secure tunnel from your Mac across the Internet and straight into your corporate network. All data passing through this tunnel is heavily encrypted to the Internet eavesdropper it looks like so much undecipherable gobbledygook. And it s cheap whether you re accessing the Internet via your home DSL a local ISP number from a hotel or wirelessly from your stool at Starbucks. Remember though that VPN is a