What is the Difference Between NAT and NAPT?
🆚 Go to Comparative Table 🆚The main difference between Network Address Translation (NAT) and Network Address and Port Translation (NAPT) lies in the number of IP addresses they can handle and the way they manage traffic.
NAT is a process that modifies the IP address in the header of an IP packet as it travels through a routing device, allowing a different set of IP addresses to be used for traffic within a Local Area Network (LAN) and a unique set of IP addresses for traffic over the Internet. The simplest form of NAT provides a one-to-one transformation of IP addresses.
NAPT, on the other hand, is an extension of NAT that allows multiple private IP addresses to be mapped to a single public IP address. This involves a many-to-one translation of IP addresses and is the most widely used NAT method. NAPT is sometimes referred to as simply NAT due to its prevalence.
In NAPT, many IP addresses are mapped to a single IP address, which could cause ambiguity when routing returned packets. To overcome this issue, NAPT uses TCP/UDP port information in outgoing traffic to enable the correct routing of returned packets to the requester.
Comparative Table: NAT vs NAPT
Here is a table comparing the differences between Network Address Translation (NAT) and Network Address and Port Translation (NAPT):
| Feature | NAT | NAPT |
|---|---|---|
| Definition | NAT is the process of modifying the IP address in the header of an IP packet as it travels through a routing device. | NAPT is an extension of NAT that allows many IP addresses to be mapped to a single IP address. It is also known as PAT (Port Address Translation), IP masquerading, NAT overload, and many-to-one NAT. |
| IP Address Transformation | NAT provides one-to-one transformation of IP addresses. | NAPT involves many-to-one translation of IP addresses. |
| Port Information | NAT does not involve port numbers. | NAPT uses TCP/UDP port information in outgoing traffic to avoid ambiguity when routing returned packets and to maintain a translation table. |
| Usage | NAT is used to slow down the rate of depletion of available IP addresses by translating private IP addresses into public IP addresses. | NAPT is the most widely used NAT and is often referred to as NAT. It is used to map multiple private IP addresses to a single IP address or a small group of public IP addresses. |
In summary, NAT is a process that modifies IP addresses in IP packets to allow one set of IP addresses to be used for traffic within a LAN while using a different set of IP addresses for external traffic. NAPT, on the other hand, is an extension of NAT that maps multiple private IP addresses to a single IP address, using port numbers to avoid ambiguity when routing returned packets.