Network Address Translation (NAT)
Used, by most firewalls, to shield a private network from public network
- Translates between private addresses inside a network and public addresses outside the network
- Done transparently (unnoticed by external computers)
- Internal IP addresses remain hidden
Performed by NAT proxy servers
- Uses an address table to do translations
- Ex: a computer inside accesses a computer outside
- Change source IP address to its own address
- Change source port number to a unique number
- Used as an index to the original source IP address
- Performs reverse operations for response packets