IP address

All computers attached to an IP network (such as the Internet) are uniquely identified by a 32-bit number, usually expressed in decimal notation and with each byte (or octet) separated by a period. Because each portion of the address specifies two bits, the decimal range is between 0 and 255 for each of the four bytes.

For example:10.191.31.10

If you ever see an IP address expressed in decimal notation with a number ING higher than 255, the address is not a valid IP address.
This address must be unique to the specific computer to which it is assigned— no other computer can have this address if it is attached to the same internework (i.e., the Internet). If two computers ever do have the same address, unpredictable routing errors will result. IP addresses are analogous to house addresses in that no two are ever the same and each element (in the case of house addresses, elements would be states, cities, streets, and numbers) is increasingly specific.

Subnets

IP addresses are not simply assigned at random. All computers on the same data link network are within the same subnet, or range of IP addresses. For instance, if you have an office Ethernet of 25 computers, all 25 computers would have IP addresses within the same short range.

The following example explains how IP addresses are assigned and how networks are submitted, or divided into IP networks. Let’s say that BT&T. a telephone company and Internet service provider (ISP), has been assigned th 10 address range. Within that range, BT&T is able to split up and sell ranges of IP addresses.

Now let’s say that American Internet, a regional ISP that serves the east coast, purchases from BT&T high-capacity network connections and the right:

to act as a second-tier Internet service provider. BT&T assigns the 191 range of its 10 address range to American Internet, which is now free to assign any addresses more specific than 10. 191.

Digital Widgets, a small company that makes a digital version of the ubiquitous widget and has 200 computers, leases a Ti service and the ability to assign its own IP addresses within the company from American Internet. American Internet gives Digital Widgets the 64 address range so that Digital Widgets is free to assign any IP address more specific than 10.191. 64 to their own computers.

Sara, the forward-thinking network administrator of Digital Widgets, assigns the IP addresses 10.191.64.1 to the router attached to the Ti line. She assigns th address 10. 191.64.2 to the corporate server and sets up DHCP on the server to automatically assign the remaining addresses to client computers as they attach to the network.

DHCP is a protocol that dynamically assigns IP addresses to clients as they request them. DHCP is explained in the last section of this article

When Sara boots her networked client computer, it automatically receives the IP address 10.191.64.3 because it was the first computer to request a DHCP lease.

the articles will continue when i have more time on my hands

By: Max Tridad

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