What is a Public IP Address?

An IP Address comprises a series of numbers in 4 groups separated by a dot. The current version of IP addresses is IPv4 (IP version 4). There is an updated version IPv6 (IP version 6), which has created a vast number of new IP addresses. Each number is unique and is used to identify any device that has internet capabilities.

Some networks will have separate but linked, router, and modem. Throughout the home, there will be various devices that need to access the internet. Among these devices might be a desktop computer, a laptop, a tablet, several cellphones, a printer, and a baby monitor, even security cameras.

IP addresses are held at various locations throughout the internet in DNS caches. Each device will have its own DNS cache, and when it is sending data to a frequently used website, it will send the data to the router along with the IP address of where it's going. This saves time, as there is no need for the router or any device on the internet to have to search for that IP address.

There are two types of IP addresses: Public IP addresses, and Private IP addresses. Within both of these types, there are two further types: Dynamic IP address and Static IP address. This article will explain what is meant by all of these terms.

Private vs. Public IP Addresses

Private IP Addresses are prevented from accessing the internet. Devices on the internet are programmed to reject any attempt by a Private IP address to connect with them. Contact with the internet can only be done through a device with a Public IP address. When someone wants to connect to a website, for example, the computer being used will send a request down to the router that controls the home network.

This connection with the router is through a Private IP address. The router recognizes the device the request has come from. The domain name for the website is converted into a public IP address, and this gets sent to the server that hosts that particular website. The server uses the Public IP address to identify the website and submit the request to it. Then, the whole operation runs in reverse, as the website sends back the requested page(s) using the Public IP address it has been given.

When it reaches the home networks router, the request is sent to the right computer using its Private IP address. The whole operation is made possible by the Network Address Translator (NAT) that is contained within the router. It uses this to determine the correct Public IP address where it must send the computer's request.

Range of Public IP Addresses

IP addresses that fall within these ranges are reserved for private use:

  • to
  • to
  • to

Public IP addresses fall in the range 1 to 191 but exclude the first two ranges listed. Most private IP addresses fall in the 192.x.x.x range. These numbers are assigned by the Internet Assigned Numbers Authority (IANA) and are IPv4 numbers.

Finding Your Public IP Address

The majority of users do not know their network router's IP address. Most will never need to know it, but there could be situations where it is required. When problems arise, and troubleshooting is necessary, is one example. Another is using a remote access program when the user is away from home. From, say, Paris, remoting into a computer in Dallas means entering the public IP address of the home router. Without it, no connection can be made.

There are tools available on the internet, where, with just one click, the public IP address, plus other useful information, is displayed. The downside of this is that it can only be done from a home-based computer. It is also possible to find a network's Public IP address via the routers administration page.

Getting to the administration page requires the default gateway IP address of the router.

  • On Windows, go to¬†Command¬†Prompt. Use¬†the ipconfig¬†command.
  • For macOS users, click on the Apple menu¬†and then select System Preferences. Once that has opened, click on the Network¬†icon. Then select the appropriate network connection ‚Äď Wi-Fi or wired ‚Äď and hit the Advanced¬†button. On the screen that now appears, choose the TCP/IP tab. Under Router, the default gateway IP address will be listed.

Why Do Public IP Addresses Change?

IP addresses can be either dynamic or static. IP addresses that change are called dynamic. Those that don't are static. In the early days of Internet Service Providers (ISP), users tended to be on the internet for short periods and then would disconnect. Dynamic IP addresses developed so that more than one user could use them.

In turn, this meant that the ISPs did not need to purchase more IP addresses than they actually needed. With the growth of the internet and the burgeoning numbers of websites, static IP addresses came into use.

Websites have to be available 24/7, so they need unchanging IP addresses. If they were to use dynamic IP addresses, the Domain Name System (DNS) cache would have to be renewed every time the IP address changed. As a result, there could be periods where a website could be offline. Conversely, a static website for a home network would not be a good idea. Hackers would find it too easy to break into the network.

Home networks usually are supplied with a dynamic IP address. Dynamic IP addresses also cost less. Static IP addresses require much more management than dynamic ones and therefore are more expensive to run.

How to Hide a Public IP Address

It is not possible to hide a public IP address from an ISP. All the internet traffic generated by a home network has to go through them before it can be sent anywhere else on the internet. However, it is possible to hide an IP address from websites that are visited. Also, it is possible to encrypt data being transferred, to hide it from the ISP. This process is done by filtering data through a Virtual Private Network (VPN).

Any website that is accessed through the internet can easily identify the public IP address of the user who made the request to visit. Then, it is possible for that website to carry out a hunt on an IP searching website. Once they have found out the IP address of the network that made the request, they can carry out another search, which will link the request to a particular home network. This helps hackers and dubious websites to reach that home network.

The solution to this problem is to use a VPN service. When using this service, the VPN will insert another ISP at the end of the website request. This new ISP inserts a false; IP address into the request and the website only sees that false; IP address.

When security is an issue, there might be concerns about an ISP being legally required to give up information about who is accessing certain websites. VPNs often are based in countries where this handing over of information is not required by law. VPNs can be found that are free, or there are others that charge a fee. If security is a concern, using a VPN that does not save the traffic records would be a good idea.

Other Information

Home routers are assigned two IP addresses. One is a private IP address, which is also the router's default gateway IP address. It will use this address to communicate with other private networks over the internet. The second IP address is the public IP address that the router needs to
communicate with the internet at large.


Jonathan has a masters degree in Computer Engineering, loves programming and creating web services that help people perform various tedious tasks.

In his free time, he writes informative articles about networking and routers for RouterReset.com

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