Virtual Private Networks (VPNs)

The problem of remote access has appeared many times in this book. This problem has actually been an important issue throughout the evolution of TCP/IP. How do you connect computers that are not close enough for a LAN-style cable connection? System administrators have always relied on two important methods for remote connections:

  • Dial-up— A remote user connects through a modem to a dial-up server, which acts as a gateway to the network.

  • Wide area network (WAN)— Two networks are connected through a dedicated leased line connection through a phone company or Internet provider.

Both these methods also have disadvantages. Dial-up connections are notoriously slow, and they are dependent on the quality of the phone connection. ...

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