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1.3 Internet Protocol Addressing Solutions

Private IPv4 Addresses

  • Used for network communication on the internal network
  • Referred to as an RFC1918 IP address
  • Internal or private IP addresses are not reachable by external devices over the internet
  • These IP address ranges can be used on multiple networks, and not reachable through the internet
  • Network Address Translation (NAT) server is used to facilitate communication externally
  • NAT server can be a router or firewall which translates the the private IP to a public IP to ensure external communication.
  • NAT server will have a limited number of public IP addresses assigned to it, which minimizes the use of these public IP addresses
  • Port Address Translation (PAT) is utilized to reduce the use of public IP addresses.
  • Multiple devices can connect to the internet using only one public IP address for communication. PAT is used by routers to facilitate communication.