NAT

Network Address Translation (NAT) is a way to map multiple private IP addresses inside a local network to a public IP address before transferring the information onto the internet.

1. Static NAT
   1. Permanent one-to-one mapping between a public and private IP address
   2. Usually used for servers
2. Dynamic NAT
   1. Uses a pool of available public IP addresses which are given out as-needed, first-come-first-served
   2. Requests are dropped once the pool runs out
3. PAT
   1. Port Address Translation, also called Dynamic NAT with Overload, is a type of dynamic NAT that bands several local IP addresses to a singular public one using Layer 4 ports
   2. It can use one or more public IP addresses
      1. The first public IP address is assigned like normal in Dynamic NAT
      2. The last public IP address is translated using port numbers

Metadata

OSI or TCP/IP Layer

CCNA Exam Topic

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