Private Vs Public IP Address

Public IP addresses are used for global communications on the Internet, while private IP addresses are typically used for internal LAN communications


Public IP addresses are used for global communications on the Internet, while private IP addresses are typically used for internal LAN communications and to communicate with the Internet through Network Address Translation (NAT).

What is a public IP address?


A Public IP Address is a unique identifier used to identify and communicate on the Internet. It is assigned to network devices (such as computers, routers, or servers) so that they can communicate with other devices on the global Internet. Public IP addresses are typically assigned by Internet Service Providers (ISPs) to their customers.

Here are some characteristics and uses of public IP addresses:

  1. Uniqueness: Every public IP address should be globally unique to ensure that devices on the Internet can accurately identify and communicate with each other.

  2. Routing: Public IP addresses allow data to be transferred between routers on the Internet so that data can be delivered from the sender to the receiver.

  3. Access the Internet: Many devices require a public IP address to access the Internet. This includes personal computers, smartphones, servers and other network equipment.

  4. Host Identification: A public IP address is used to uniquely identify a host (computer or device) so that other devices can find and communicate with it.

  5. Port Forwarding: Public IP addresses allow port forwarding rules to be set up on the router to route specific types of traffic to specific internal devices (for example, routing web traffic to a web server).

  6. Security: Public IP addresses can also be subject to security threats, so appropriate security measures must be taken to protect devices connected to these addresses from malicious attacks.

It's important to note that public IP addresses are usually dynamically assigned, meaning that the Internet Service Provider can periodically change the IP address assigned to you. Additionally, IPv4 and IPv6 are two different IP address protocols that are used to allocate and identify public IP addresses. IPv4 is an older protocol, while IPv6 is a newer protocol designed to address the shortage of IPv4 addresses. On the Internet, both types of IP addresses are in use.

What is a private IP address?


A private IP address is an IP address used for communication within a private network; these addresses are not directly accessible from the public internet. Private IP addresses are typically used within a home, business, or organization's internal network to connect devices in a local area network (LAN) so that they can communicate with each other and access shared resources, such as printers, file servers, and routers.

Private IP addresses are assigned based on certain IP address ranges defined by the Internet Engineering Task Force (IETF) that are reserved for private network use and are not used for global routing on the Internet.

If you want to connect your internal network to the Internet, you typically need to use Network Address Translation (NAT), or a method of mapping private IP addresses to public IP addresses, to enable communication. This helps secure your internal network and enables multiple devices to share a public IP address.

Key differences between public and private IP addresses

There are many differences between public IP addresses and private IP addresses, and they play different roles in network design and management. Public IP addresses are used for global communications on the Internet, while private IP addresses are typically used for internal LAN communications and to communicate with the Internet through Network Address Translation (NAT).

FeaturePublic IP AddressPrivate IP Address
Access RangeAccessible and communicable globallyTypically accessible only within a specific LAN or private network
UniquenessMust be unique on the internetCan be reused within a LAN but must be unique globally
Allocation MethodAssigned by Internet Service Providers (ISPs) to user devicesAssigned by LAN administrators to internal devices
IP Address RangeTypically belongs to IPv4 or IPv6 address rangesUsually falls within the private IP address range, such as
Access PermissionsPublicly accessible, used for hosting public servers and websitesTypically accessible only within the private network, not directly exposed to the internet
SecurityMore susceptible to network attacksRelatively more secure as it is not directly accessible on the internet
NAT (Network Address Translation)Usually not needed for global routabilityNAT is often needed to map private IPs to public IPs for internet communication
CostTypically incurs additional fees for obtaining a public IP addressUsually no additional cost, as it is for internal use within a private network

Public and private IP address ranges

  1. Private IP Address: Private IP addresses are used on internal networks, such as home networks or corporate intranets. The following are the private IP address ranges for IPv4:

    • Class A: to
    • Class B: to
    • Class C: to

    In addition, the IPv6 private address range starts with the prefix fc00::/7.

  2. Public IP Address: Except for private IP addresses, the rest are public IP addresses.

Please note that these are standard IP address allocation ranges, but there may be some variations in actual use, especially in corporate networks, and can be customized as needed. If you are setting up a network or have specific IP address needs, it is recommended to refer to the relevant specifications and documentation to ensure correct configuration.

How to tell if an IP address is public or private?

The public or private nature of IP addresses is determined by their range. IPv4 and IPv6 addresses have different private address ranges.

IPv4 address:

If an IPv4 address is within the previously mentioned range, it is private. Otherwise, it is public.

IPv6 address:

The private nature of an IPv6 address is usually determined by the address prefix

Private IPv6 Address: Private IPv6 addresses typically include the following prefixes:

  • **ULA (Unique Local Address) prefix: ** fc00::/7
  • Link-Local prefix: fe80::/10
  • Loopback prefix: ::1/128

An IPv6 address is private if its prefix is one of the above private prefixes. Otherwise, it is public.

Can public IP addresses be tracked?

2 Simple Ways To Trace an IP Address

Public IP addresses can be traced to their physical location or user, but the difficulty and accuracy of tracing are affected by a variety of factors. Here are some factors that affect IP address tracking:

  1. Internet Service Provider (ISP) Information: Each IP address is associated with a specific ISP. ISPs often log which user used a specific IP address, so legal agencies and law enforcement officials can contact the ISP to obtain information about a specific IP address. This can be used to track activity or determine the owner of an address.

  2. Geographical location information: Through the IP address, its geographical location can be roughly determined. This is often called a geolocation service, which uses a database of IP addresses to estimate the city or region where the IP address is located. However, the accuracy of this method is limited and can usually only provide general geographical location information, rather than being precise to specific streets or buildings.

  3. Anonymous Proxies and Virtual Private Networks (VPN): Using an anonymous proxy server or VPN service can hide a user’s real IP address, making tracking more difficult. In this case, only the VPN service provider or anonymizing proxy information can be used for tracking.

Can private IP addresses be tracked?

Private IP addresses are generally more difficult to trace directly to a specific physical location or user because they are typically used within an internal network or local area network rather than directly connected to the Internet. Private IP addresses are unique only within a specific network and are not routed globally. We generally cannot trace private IP addresses.

If you want to track or lookup a IP address, try our free IP address lookup tool!

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