Overview of NAT
Definition
Network Address Translation (NAT) translates the IP address in an IP datagram header to another IP address.
Purpose
The rapid development of the Internet brings an increasing number of network applications. Exhaustion of IPv4 addresses has become a bottleneck for the network development. IPv6 can solve the problem of IPv4 address shortage, but numerous network devices and applications are based on IPv4. Major transitional technologies such as classless inter-domain routing (CIDR) and private network addresses are used before the wide use of IPv6 addresses. NAT enables users on private networks to access public networks. When a host on a private network accesses a public network, NAT translates the host's private IP address to a public IP address. Multiple hosts on a private network can share one public IP address. This implements network communication while saving public IP addresses.
Benefits
- Protects private networks against external attacks, greatly improving network security.
- This function controls not only access to external networks from internal hosts, but also access to the internal network from external users.