The Basics of Routers and Network Address Translation (NAT)

As was explained in detail in Chapter 22, a router is a device that connects two disparate IP networks together and determines how datagrams get from one network to another.

Note

A datagram is a packet of digital information. It contains addressing information as well as the data to be transmitted. Not all datagrams necessarily take the same route to get to their destinations, even if they all have the same origin.

To better understand what a router does, look at the following two figures. Figure 28.1 shows two sample networks for a fictional global company that has offices in New York and Denmark.

Figure 28.1. A sample global network for a fictional company, with several hosts in ...

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