What is NAT Overload and NAT*?

NAT stands for network address translation. Basically it will bind you local IP with public ip to go to internet. inorder to access internet you will require a public ip. you local ip are not allowed to go outside and access internet. We also use NAT to save public IP's. you can use many to one or one to one NAT. with many to one option you can bind complete subnet with one public ip e.g192.168.1.0/24 (local subnet) with public ip lets say (200.200.1.1) so any request from this local range will always go out with the200.200.1.1 public ip. NAT comes with PAT (port address translation). overloading isdone in the router it self. nat overload will pick the public address which is associated with you wan interface or with local internet face with public address and bind your local ip with this public address to go out to the internet.

NAT overload use port which means many private addresse is translated using different source port but with single Public addresse so we can use Public ip addresee efficently for example our network use192.168.100.0/24 network which is Private addresee in order to access the internet we we need only one public addresse in NAT overlod sometimes refere as PAT( port addresse Translation) by using single public addrsee (199.45.78.45) but different sourece port addresse we can manage to allow all254 user access internet

translation table look like this

Source Ip before translation        Source Ip after translation

     192.168.100.10                             199.45.78.45:3546

     192.168.100.11                             199.45.78.45:3647

     192.168.100.12                             199.45.78.45:3548

But in the case of NAT* we use one to one Mapping of Public ip addresse to Private addresee so we need more public ip addresee so  using NAT overload is less expensive and efficent

modified form of dynamic NAT where the number of inside local addresses is greater than the number of inside global addresses

NAT is  network address translation. It will bind local IP with public ip to  connect internet. to access internet we require a public ip. local ip are not allowed to go outside and access internet. We  use NAT to save public IP's. we can use many to one or one to one NAT.

NAT is method of translating private IP addresses into public IP addresses.

NAT Overlooad is just like NAT but uses same public IP for more than one private IP, and use the ports to distinguish between the private IPs.

NAT

Short for Network Address Translation, an Internet standard that enables a local-area network (LAN) to use one set of IP addresses for internal traffic and a second set of addresses for external traffic.PAT / NAT overloaded

Short for port address translation, a type of network address translation. During PAT, each computer on LAN is translated to the same IP address, but with a different port number assignment.

Network address translation (NAT) is a methodology of remapping one IP address space into another by modifying network address information in Internet Protocol (IP) datagram packet headers while they are in transit across a traffic routing device.

NAT overload overcomes this limitation by allowing internal hosts to share external IP addresses. To keep the connections apart, in addition to swapping the internal IP for an external one, the router can change the source port of the outgoing traffic