NAT

Network Address Translation (NAT) is a networking technique that allows multiple devices on a local network to share a single public IP address. This is accomplished by translating the private IP addresses of devices on the local network into a single, public IP address that is used to communicate with the internet. NAT can help conserve IP addresses, improve security, and enable connectivity for devices on a local network.

PAT

Port Address Translation (PAT) is a technique used in network address translation (NAT) that enables a single network device, such as a router, to translate the IP address and port number of packets passing through it. This allows multiple devices on a local network to share a single public IP address and access the internet. PAT is commonly used to conserve IP addresses and improve network security by hiding the internal network structure from external devices.

NAT commands on a cisco router

1. ip nat inside source list interface overload
2. ip nat inside source static
3. ip nat inside
4. ip nat outside
5. ip nat enable

Explanation of the above commands respectively

• First command specifies the inside interfaces and the source IP addresses that will be translated, as well as the interface and IP address that will be used for the translations.
• Second command specifies a static NAT mapping, which translates a specific local IP address to a specific global IP address.
• In third and fourth command uses the ip nat inside and ip nat outside commands to identify the inside and outside interfaces on the router.
• Fifth command uses the ip nat enable command to enable NAT on the router.

To verify type this in enable prompt:

ip nat inside source list 1 interface Ethernet1 overload