Networking - Networking Basics - Discussion

Discussion :: Networking Basics - Networking Basics (Q.No.2)


What flavor of Network Address Translation can be used to have one IP address allow many users to connect to the global Internet?

[A]. NAT
[B]. Static
[C]. Dynamic
[D]. PAT

Answer: Option D


Port Address Translation (PAT) allows a one-to-many approach to network address translation.

Senthil said: (Aug 15, 2012)  
I can't understand the answer. Pat means port address translation. Then how many users can connect to global internet.

Salim said: (Oct 6, 2012)  
What the different between NAT and PAT ?

Soujanya said: (Oct 18, 2012)  
PAT-PORT ADDRESS TRANSLATION; NAT-NETWORK ADDRESS TRANSLATION. In my sense both are similar both share one ip address. In simple words the PAT is the NAT overloading where it uses one ip address for all clients to multiple ports. Whereas as a standard NAT is one-to one ip address relation.

Smriti said: (Jan 18, 2013)  
Can anyone give brief description about NAT and PAT?

Sarita said: (Feb 26, 2013)  

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.


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.

Vidushi said: (May 3, 2013)  
NAT(Network Address Translation):--> One ip one Port.
PAT(Port Address Translation) :--> One ip multiple port.

Sintu Yadav said: (Jun 14, 2013)  
NAT not understand what is main difference between NAT and PAT?

Someone said: (Aug 17, 2013)  
Basic For NAT : With the explosion of the Internet and the increase in home networks and business networks, the number of available IP addresses is simply not enough. This is where NAT comes to the rescue. Network Address Translation allows a single device, such as a router, to act as an agent between the Internet (or "public network") and a local (or "private") network. This means that only a single, unique IP address is required to represent an entire group of computers.

NAT is used by a device and do mapping of an unregistered IP address to a registered IP address on a one-to-one basis.

NAT that maps multiple unregistered IP addresses to a single registered IP address by using different ports. This is known also as PAT (Port Address Translation).

Khushboo Ghag said: (Nov 26, 2013)  
Even I didnt get the difference between NAT and PAT. I know individual definitions but as far as difference is concerned...not clear yet. From Configuration point of view the difference while applying at router is : PAT uses an additional word i.e. overload.

Ex: ip nat inside Source list [access list number] pool [pool name] PAT.

For NAT the command remains same but without overload.

Jay said: (Dec 17, 2013)  
NAT is a protocol that translates inside addresses (private address) into global inside address (public ips). Its developed to hold the shortage of IPv4. It allow to have thousands of hosts with private ip address to be translated in public addresses.

PAT, is the same thing as NAT. The difference is, instead of translating ip's, PAT translate into ports. Its ensure a company that have ONLY one public ip address to communicate with external hosts.


- If we have like 200 hosts in a company and have more than 2 addresses, we use NAT;

- If we have like 200 hosts in a company and have only 1 public address, we use NAT and PAT (if we have many internal hosts to a single public address it can cause problems).

Rajashree Kamble said: (Jan 9, 2014)  
NAT: NAT means Network Address Translation. Or PAT: It means Port Address Translation. And both are consist of similar to each other only difference is that NAT is One IP one port and PAT is One ip multiple port.

Nandi said: (Jul 23, 2014)  
Say what is dynamic and static?

Rahul Shinde said: (Jul 25, 2014)  
Hey Nandi, for static NAT- We are giving the manual ip to every host in the network which will be converted into public ip address by NAT.

for Dynamic NAT - We are providing the pool or set of public IP addresses to all hosts instead of giving it manually to every host.

Udhay said: (Dec 23, 2014)  
Port has address based on physical media. It is 100% correct.

Pavan said: (May 18, 2015)  
In which type of networking NAT and PAT using?

Lawrence said: (Aug 5, 2015)  
Can some give practical scenario about the differences between Nat and Pat?

Vidhya said: (Oct 29, 2015)  
What is the concept of PAT?

Virat said: (Jan 9, 2016)  
PAT (Port Address Translation) includes ports in addition to IP addresses.

Many-to-one translation. Maps multiple IP addresses to 1 or a few IP addresses. Unique source port number identifies each session. Conserves registered IP addresses.

Also called NAPT (Network Address Port Translation) in IETF (Internet Engineering Task Force) documents.

Kirti Paliwal said: (Feb 8, 2016)  
Can you please explain the above example of 200 hosts in company?

Vijay said: (Feb 18, 2016)  
Ex. When 2 host access then the IP address of host are port no is 80 also 80 when the router receive packet from

It will change port number for ex. Public IP is P.81 for P.No 80 and P.No 82 for P.No 80. In router there will be change in port addr of host that is called PAT.

Rohan said: (Apr 27, 2016)  
What are the uses of Port Address Translation (PAT)?

Keerthana said: (Jul 16, 2016)  
Please give practical application for NAT and PAT.

Ramkripal said: (Oct 10, 2016)  
What is pat? explain.

Divyajai said: (Mar 21, 2017)  
It should be Static.

Yogesh Singh said: (Sep 10, 2017)  
Static NAT (Network Address Translation) - Static NAT (Network Address Translation) is a one-to-one mapping of a private IP address to a public IP address. Static NAT (Network Address Translation) is useful when a network device inside a private network needs to be accessible from the internet.

Dynamic NAT (Network Address Translation) - Dynamic NAT can be defined as a mapping of a private IP address to a public IP address from a group of public IP addresses called as NAT pool. Dynamic NAT establishes a one-to-one mapping between a private IP address to a public IP address. Here the public IP address is taken from the pool of IP addresses configured on the end NAT router. The public to private mapping may vary based on the available public IP address in NAT pool.

PAT (Port Address Translation) - Port Address Translation (PAT) is another type of dynamic NAT which can map multiple private IP addresses to a single public IP address by using a technology known as Port Address Translation.

Here when a client from inside network communicate to a host on the internet, the router changes the source port (TCP or UDP) number with another port number. These port mappings are kept in a table. When the router receives from the internet, it will refer the table which keeps the port mappings and forward the data packet to the original sender.

Astewul Birhanu said: (Sep 16, 2017)  
Network Address Translation (NAT) and Port Address Translation (PAT) both map IP addresses on an internal network to IP addresses on an external network. Which method of address translation you use depends on the types of networks that you are translating and the number of available IP addresses that you have.

If you are connecting a site to the network to a site in the network, you could use NAT to translate IP addresses to available IP addresses so that hosts on the network can access data and use network resources on the network. However, for this scenario to work, you must have an address pool that contains enough available IP addresses on the network to accommodate every host on the network, because NAT requires a one-to-one relationship when translating IP addresses.

PAT attempts to use the original source port number of the internal host to form a unique, registered IP address and port number combination. For example, two hosts that have been assigned the IP addresses and, respectively, could send traffic to and receive traffic from the Internet by using the single public IP address If that port number is already allocated, PAT searches for an available alternate source port number. Therefore, the host at IP address could access the Internet by using the public IP address and source port combination of Meanwhile, the host at IP address could access the Internet by using the IP address and source port combination of

Naanthan said: (Jan 3, 2018)  
What are PAT and NAT? I want a clear explanation.

Abshir Aadan said: (Jan 11, 2018)  
NAT is static network address translation that is used to convert one IP private of local translate into public one ip address private allow many users to connect to the global internet.

PAT:-is dynamic port address translation that is used to convert multiple ip private to public IP address.

Multiple IP address privates allow many users to connect to the global internet.

Addis Alem said: (Feb 14, 2018)  
Network address translation (NAT) is a router function that enables public and private network connections and allows single IP address communication. While there are many public networks worldwide, there is a limited number of private networks.

Gaurav said: (Dec 27, 2020)  
Why can't NAT?

I don't understand, Please explain.

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