If a NAT's job is to create mappings between internal ip/port pairs and external ip/port pairs with one Internet-routable IP address, does a NAT need a private IP address for itself? I think one public IP address all a NAT needs to function. The only thing I can think of is that we need its private address to connect to it for the configuring purpose. I know this may be a trivial question but I can't seem to find a clear answer.

  • There are multiple forms of NAT (you are referring to the NAPT variant), and it is really just replacing either or both the source and destination address in a packet header. It does not matter if it is public or private addressing because IP has no concept of public or private addressing. Private addressing is just that the ISPs have agreed not to route traffic on the public Internet in certain IP ranges.
    – Ron Maupin
    Mar 4, 2020 at 11:24

3 Answers 3


Most often, a NAT device is modeled as a router, using IP addresses for its (L3) interfaces. So, you'd need at least two addresses, one from each network to translate from and to translate to. These addresses can also both be private or (rarely) both public.

However, NA(P)T can also be done on any suitable device that the traffic to be translated runs through, like a bridge/switch, without using any IP address for itself.


No, NAT doesn't need to have a private IP. You can also NAT a private IP address to another private IP address.

  • 3
    Or, public address to public address.
    – Ron Maupin
    Mar 6, 2020 at 0:03

Basically there are several type of Nating method depends upon our business requirements we can select which ever we wants

Types of NAT

  1. NAT overload

NAT overload is configured in perimeter layer3 devices to map one public ip address to many private address . Generally NAT overload is used to connect internet .

  1. Static NAT

Static NAT or one to one nat is used to map one private address to one public address . Static nat is used to access web server hosted in internal networks from internet .

  1. Dynamic NAT

Dynamic NAT is used to map many public address to many private address . This is highly secure interm of security.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.