If you have ever paid much attention during most tech support conversations then you know that your computer has an IP (otherwise known as Internet protocol) address to it. As you might extrapolate from that, other computers all over the world also have their own IP addresses, as well. And with some limitations, nearly every computer has an IP address. However, there are some occasions in which there is no unique IP address information available for a computer. It is in some of these nooks and crannies that hackers and their malware tend to hide, like pestilence stalking the night for something to feed on. And in this kind of environment, what they are feeding on is your information and your computer’s hardware power.
One of the types of situations where a computer might not have its own IP address is when it is sitting on a local area network (also known as a LAN). Sometimes the LAN itself serves as what the Internet perceives as the computer, and every computer which is subordinate to the LAN itself is known only by its nickname. In that kind of an environment, it can be easy for a piece of malicious code to strike out, and be difficult to detect (and thus eliminate). Since many hackers are aware of this kind of situation, they will frequently hide out in places where security may be lax, such as the LANs of a college campus.
Another time in which a computer may not have its own IP address (other than, obviously, when it is offline) is when the computer is connected to the Internet through an internet service provider that has geographically based IP addresses about it. In these kinds of situations, the ISP typically knows the computers under its aegis in individual and proprietary ways. When law enforcement personnel isolate a hacker’s activities down to a particular area, the ISP can usually point them right where to go.