To get IP information
Click on "Start", then "Run", type in "command" and press "Enter". Type in "ipconfig /all" and press "Enter"

Dynamic vs Static IPs Most routers assign dynamic IP addresses by default. They do this because dynamic IP address networks require no configuration. The end user can simply plug their computer in, and their network will work. When IP addresses are assigned dynamically, the router is the one that assigns them. Every time a computer reboots it asks the router for an IP address. The router then hands it an IP address that has not already been handed out to another computer. This is important to note. When you set your computer to a static IP address, the router does not know that a computer is using that IP address. So the very same IP address may be handed to another computer later, and that will prevent both computers from connecting to the internet. So when you asign a static IP addresses, it's important to assign an IP address that will not be handed out to other computers by the dynamic IP address server. The dynamic IP address server is generally referred to as the DHCP server.
It is very important to setup a static IP address, if you are going to use port forwarding. When you have port forwarding setup, your router forwards ports to an IP address that you specify. This will probably work when you initially set it up, but after restarting your computer it may get a different IP address. When this happens the ports will no longer be forwarded to your computer's IP address. So the port forwarding configuration will not work.

IP address (Internet Protocol) An IP address refers to a unique number assigned to each computer on the Internet. The IP number is called an "address" because it serves the same purpose as a home address - it allows each machine on the Internet to be located by a numerical scheme.
An ISP might offer either a dynamic or static IP address. A static IP address is a permanent address, while a dynamic address changes with each new Internet session. Every ISP has a unique range of available IP addresses.
A domain name, such as www.wiseGEEK.com, also maps to a numerical IP address. In this case, the IP address is 69.56.209.194.

If you are working on a Windows machine, you can view your current IP address with the command WINIPCFG and IPCONFIG for Windows 2000/XP.

Static IP address: a unique number that is assigned to each computer by an Internet service provider to be its permanent address on the Internet. Computers use IP addresses to locate and talk to each other on the Internet, much the same way people use phone numbers to locate and talk to one another on the telephone.
It would be simple if every computer that connects to the Internet could have its own static IP number, but when the Internet was first conceived, the architects didn't foresee the need for an unlimited number of IP addresses. Consequently, there are not enough IP numbers to go around. To get around that problem, many Internet service providers limit the number of static IP addresses they allocate, and economize on the remaining number of IP addresses they possess by temporarily assigning an IP address to a requesting Dynamic Host Configuration Protocol (DHCP) computer from a pool of IP addresses. The temporary IP address is called a dynamic IP address.

Subnet Mask
A netmask is a code of numbers that is used to transfer messages correctly among machines in the same subnet. It works together with a network's router to determine where the data goes when it is received.
Netmasks are used to identify which portion of an IP address represents the network address and which portion represents the machine address. A netmask is essentially a mathematical mask that hides a portion of an IP address and replaces it with other numbers. Netmasks are used in computer networks of all sizes.

Netmask is a term that is commonly used in the computer and internet technology industries. The most common netmask is a 32-bit mask. 32-bit masks were created to be used for two main purposes; first, to administer internet sites and divide an IP address into what are called subnets and second to specify the available hosts for the networks and determine where data goes when it is received by the router. Netmasks are essential for successful internet computer networking.
A 32-bit netmask is a component of computers that are capable of transferring data 32-bits at a time. There can also be 24-bit netmasks that are functional for smaller networks.

The netmask hides the network section of an IP address so that only the host computer or machine remains visible to network users. This is done by replacing the numbers in the IP address with a string of 1's and 0's. A commonly used netmask is 255.255.255.0 because 255 is the decimal equivalent or sum of a string of 8 binary 1's. The 255's mask the network, and the 0 allows for the host computer part of the IP address to remain visible to anyone who accesses the network.
In a computer network the router is responsible for generating the netmask. The netmask is generated by the use of a netmask calculator. A netmask calculator is a script or a program that calculates the numbers for the netmask for the IP address. There are three classes of netmasks. They are labeled as class A, class B and class C. All classes of netmasks, A, B & C are commonly used in computer internet networks today. Different classes of netmasks are generally different lengths and are meant to be used with different sized networks and computer systems.

Network address translation (NAT) is a dynamic method of consolidation used by systems in order to minimize Internet connectivity needs. Specifically, network address translation describes the rewriting of the Internet Protocol (IP) addresses of data packets so that multiple transmissions require only one IP address. The rewriting takes place as the data passes through a network or a network firewall. This is done on a private network. In addition to the firewall, companies also use routers or even computers to perform network address translation functionality.

Network address translation commonly takes one of four forms: Static NAT, Dynamic NAT, Overloading, or Overlapping. Static NAT is translating one unregistered IP address to another, registered one. Dynamic NAT is translating one unregistered IP address to another chosen from a group of registered addresses. Overloading is a form of Dynamic NAT that translates a series of unregistered addresses to one registered one. Overlapping is translating multiple addresses from one network to another. Each method is used according to the specific needs of the company at hand.

One of the main reasons for using network address translation is the conservation of IP addresses. Many industry experts think that the explosion in demand for IP addresses will result in a global shortage created by the elimination of all the available permutations of numbers in the 32-bit IPv4 standard that dominates the Internet today. One method of addressing this concern has been the creation of IPv6, which includes 128 bits and vastly more possibilities for IP addresses. The creation of IPv6 doesn't really address the shortage problem, however. Network address translation does, by not creating new IP addresses when they aren't needed.

One drawback of network address translation is that it doesn't allow for a true connection from start to finish. In other words, if a connection originates from outside the network, then the network address translation protocols can't guarantee that the data will remain intact all the way through the process. That the original IP wasn't one associated with the network to begin with is the mitigating factor here.

On the other hand, this mitigating factor can also be a benefit. If the network address translation won't allow wire-to-wire data transfer from a source outside the network, then it naturally serves as a barrier to data streams with malicious intent. That kind of functionality can naturally serve as a security service that keeps out viruses, worms, and other dangers.

Default Gateway
The router used to forward all traffic that is not addressed to a station within the local network or local subnet. Its primary purpose in most applications is to direct Internet traffic from the local network to the cable or DSL modem, which connects to the Internet service provider (ISP).

A default gateway is the device that passes traffic from the local subnet to devices on other subnets. The default gateway often connects a local network to the Internet, although internal gateways for local networks also exist.

Internet default gateways are typically one of two types:

    1. On home or small business networks with a broadband router to share the Internet connection, the home router serves as the default gateway.

    2. On home or small business networks without a router, such as for residences with dialup Internet access, a router at the Internet Service Provider location serves as the default gateway.

Routers
Computers within a private network are each assigned a unique address in order to exchange files and share resources with one another. The network router, which routes information, will pass data back and forth among the connected computers, using the respective addresses. But how do computers on a private network connect to the Internet?

Assuming the network has Internet connectivity, the computer connected to the digital subscriber line (DSL) modem is assigned a public IP address by the Internet Service Provider (ISP). This single public IP address is used to identify the network on the Internet. Now the network's router acts as a gatekeeper between the private network and the public Internet. Using a built-in Network Address Translator (NAT), the router passes requests to the Internet using the assigned public IP address. Returning data is routed back to the public IP address, with the router determining which private IP address requested the information. In essence, the private IP address is daisy-chained to the public IP address through processes in the router.

MAC address (Media Access Control) is a unique code assigned to every piece of hardware that connects to the Internet. Internet capable phones, Network Interface Cards for desktop or notebook computers, Wireless Access Cards, and even some memory cards are among the devices that are assigned MAC addresses.

When a manufacturer creates a network capable piece of hardware they will assign the MAC address, which will usually begin with a code that is tied to the manufacturer. The MAC address will be unique to every device, even two devices of the same type.

A device's MAC address is composed of six pairs of hexadecimal numbers. The numbers are separated by colons as in the following example: 6E:51:F5:c1:11:00

MAC addresses are used at the data link layer of the OSI hardware model to allow packets to be passed directly between devices on a network. This helps to ensure that the data is sent to a physical device before being decoded and/or manipulated by a device.

A MAC address is similar to an IP address that the device also receives in that it ensures each device is unique and allows data to be passed among hardware devices. An IP address allows two devices to communicate across a LAN or network environment - normally IP addresses should also be unique and will allow the exchange of data.

Once assigned, the MAC address is used to ensure that each device connected to the LAN or other network is unique. With the recent advances in wireless networking technology, the MAC address from a wireless card can be entered into the configuration pages for a network's wireless router. From there the router can either allow or deny the device to connect based on its MAC address. This can provide additional security for the network.

Many people who use network connected devices will not ever need the MAC address to use the device. Some service providers will require the MAC address of a device to be registered with them to ensure those who are paying for or are subscribed to the service are the only users who can connect. If this is the case, the MAC address can typically be found on a sticker on the device. If the device is portable, the MAC address may be printed inside the battery compartment.

LAN  (Local Area Network)
A LAN connects network devices over a relatively short distance. A networked office building, school, or home usually contains a single LAN, though sometimes one building will contain a few small LANs (perhaps one per room), and occasionally a LAN will span a group of nearby buildings. In TCP/IP networking, a LAN is often but not always implemented as a single IP subnet.

In addition to operating in a limited space, LANs are also typically owned, controlled, and managed by a single person or organization. They also tend to use certain connectivity technologies, primarily Ethernet and Token Ring.

WAN (Wide Area Network)
As the term implies, a WAN spans a large physical distance. The Internet is the largest WAN, spanning the Earth.

A WAN is a geographically-dispersed collection of LANs. A network device called a router connects LANs to a WAN. In IP networking, the router maintains both a LAN address and a WAN address.

A WAN differs from a LAN in several important ways. Most WANs (like the Internet) are not owned by any one organization but rather exist under collective or distributed ownership and management. WANs tend to use technology like ATM, Frame Relay and X.25 for connectivity over the longer distances.

LAN, WAN and Home Networking
Residences typically employ one LAN and connect to the Internet WAN via an Internet Service Provider (ISP) using a broadband modem. The ISP provides a WAN IP address to the modem, and all of the computers on the home network use LAN (so-called private) IP addresses. All computers on the home LAN can communicate directly with each other but must go through a central gateway, typically a broadband router, to reach the ISP.

DNS: (domain name server)
Every time you use a domain name, you use the Internet's domain name servers (DNS) to translate the human-readable domain name into the machine-readable IP address.