The private IP addresses are the reserved IP address blocks that cannot be routed through the internet. Since private IP addresses are only intended to be used in private networks, they are not globally unique. The private IP address must be unique within its network (usually LAN) so that there is no conflict between two computers within its network. Due to scarce nature of IPv4 Address (i.e. approximately 4 billion IP addresses), IANA reserved private IP address blocks so that they can be used by any organization without registering them with IANA. The private IP address block can be used in homes, small businesses, or even medium and large enterprises to create their own network. Computing devices with a private IP address cannot be directly accessed from the Internet unless NAT (Network Address Translation) is used. The advanced network planning techniques have also enabled network planners to use same private IP address within different private networks thus allowing them to save valuable IP address space. A private address may also be referred to as a local IP address. It also enables to hide the identity of the users over the Internet.

By finding IP address of yourself or a person you wish to lookup, the geolocation lookup tool provide you with an estimate of where this IP address is located. American Registry of Internet Numbers, also known as ARIN, maintains the Whois Database containing contact and registration information for IP addresses. The companies requiring IP addresses obtain and register them with ARIN, and those IP addresses obtained are assigned to their users and customers. Internet Service Providers (ISPs) assign a dynamic IP address to a user when their customers connect to the Internet. Since a company may be located throughout a large region (or a country), the accuracy of geolocation may vary depending on how they assign them to their users.

To connect your computer to the Internet, you'll need an IP address. If your computer is directly connected to the gateway (or switch) provided by your ISP, your computer gets a public IP address from your ISP. However, if your computer is connected to the Internet via a router within your home network, your computer gets a private IP address from your router and your router gets the public IP address from your ISP. To learn more about public and private IP addresses, please read What is public and private IP addresses article.

IP ban is a block set up by a server to reject the request made from a particular IP or range of IP addresses. The IP ban may have been implemented automatically due to an abuse pattern detected by the server or placed manually by an administrator. IP ban is implemented to protect the server from abuse such as brute force attacks, block emails from known spammers, and limit usage by users.

Many readers of our website are contacting us for help on *allegedly* hacked IP address, and remedies for getting it back. One of the user is telling us his IP address used to be 64.3.x.y in Dallas and now it's 67.72.x.y located in Utah (per ip lookup); and hence his IP address is stolen, and his computer is running very slow and acting abnormal.

An IP address is an address assigned to a device on the Internet. A static IP address is a fixed IP address that never changes, and a dynamic IP address is an IP that is assigned by the DHCP server which may change over time.

A public IP address is an IP address that can be accessed over the Internet, and a private IP address is an IP address that is local to your private network. A public IP is a globally unique IP, while a private IP address can be reused in different networks.

Internet Protocol Version 6 (or IPv6) is a successor of IPv4 Address standard developed by IETF, which is designed to solve IPv4 address exhaustion problem. IPv4 uses a 32-bit numbering scheme to represent an IP address, which has an address space of 2³² or 4.3 billion. IPv6, on the other hand, uses a 128-bit numbering scheme (2¹²⁸) which has big enough address space for many decades to come. IPv6 is intended to replace the IPv4, but the introduction of the CIDR (Classless Inter-Domain Routing) allocation scheme in 1993 within the IPv4 prolonged lifespan of IPv4 Addresses. With the anticipation of smartphones, tablets, smart appliances, and other electronic devices joining the Internet every day, IPv4 address space will eventually exhaust. As of May 2014 per Google Statistics, 96% of Internet traffic is IPv4 and only 4% is represented by IPv6. IPv4 and IPv6 are not interoperable by design, so the transition from IPv4 to IPv6 requires a "transition mechanism" such as Stateless IP/ICMP Translation, Transport Relay, 6rd, and other IPv6 transition mechanisms to make them interoperable.

You have a private or public network with servers and workstations that are assigned static and dynamic IP addresses (either private or public IPs). You assigned them the static IP addresses due to NAT (Network Address Translation) or for public access, and dynamic IP addresses via the DHCP. Even if you kept a good record of those assigned IPs, there are times when you want to find all IP addresses of networked devices. The following procedure may be used to determine IP addresses of networked devices that are connected to your network.

IP Spoofing is a technique used to gain unauthorized access to machines, whereby an attacker illicitly impersonates another machine by manipulating IP packets. IP Spoofing involves modifying the packet header with a forged (spoofed) source IP address, a checksum, and the order value. Internet is a packet switched network, which causes the packets leaving one machine may be arriving at the destination machine in different order. The receiving machine resembles the message based on the order value embedded in the IP header. IP spoofing involves solving the algorithm that is used to select the order sent values, and to modify them correctly.