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      Network Address Translation An Internet standard 
      that enables a private network (LAN) to communicate 
      to a public network (ie Internet) 
      NAT is usually achieved with a combination of hardware and software, in 
      it's simplistic form there is a network card which is on the public facing 
      side of the network and a network card on the private side, NAT enables 
      the 2 to talk to one another (but only one another) to enable traffic on 
      the internal private network to communicate to the external network. 
      Can act as a firewall by hiding the internal network from the outside 
      world (as only the public facing network card can talk to the private 
      facing network card) 
      Enables a company to use any set of IP addresses internally without the 
      possibility of any conflict with the outside world. 
      If you are currently using a cable/adsl
      router at home chances are it 
      is using NAT. Take a look at the base or back of the router and you will 
      see 2, 12 digit numbers, probably marked A and B or WAN, 
      LAN, these are the unique identifying numbers for the public and 
      private network cards described above - called MAC addresses. 
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