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IP and network addresses

IP Addresses overview

Every computer or device that communicates over the Internet is assigned an IP address that identifies and distinguishes it from other devices on the Internet. The format of a Yale IP address is usually 130.132.xxx.xxx or 128.36.xxx.xxx. IP addresses can be different depending on what network you are on. For instance, when you connect your laptop from home, it has a different IP address than when you connect from your office or dorm room at Yale.

NIC or MAC addresses are the unique identifying number that is assigned to networking hardware when it is manufactured. These addresses are similar to a car's VIN (vehicle identification number) both that you have to know where to look to find it and it is unique to each car. This number identifies both wireless and ethernet network cards in your computer, so it is possible (even likely on a laptop) that you may need to register two network hardware addresses. The format of a NIC address is 00-00-00-00-00-00. Where you look is determined by the operating system that runs on your computer.

Together, these two addresses assist network administrators in identifying devices on a network.

Finding IP and network hardware addresses

Windows XP and Vista

1. Click the Start button
2. Click All Programs
3. Click Accessories
4. Click Command Prompt
   A black DOS box will appear with a blinking cursor
5. At the blinking cursor, type "ipconfig /all" without the quotes. Press enter.
6. Below the heading "Ethernet adapter Local Area Connection:" look for the
   - IP Address entry
   - Physical Address entry

Mac OS 10.x

Mac OS 10.4

Select System PreferencesApple Menu

Select Network Control Panel

Now, set the Show drop down menu to Built in Ethernet.

Then click on the Ethernet tab at the right. The Ethernet ID is the NIC address.

To get the NIC address for an AirPort card set the Show drop down menu to AirPort

On the AirPort tab, the first tab, the AirPort ID is the NIC address.

 

Mac 10.3 users (not pictured)

This opens the Apple System Profiler. Once open, look for "Network" in the left hand column and lcik on it. Ethernet Address field and IP Field entry.

• Under the Apple Menu Item select "About This Mac"

• From the newly opened window click the "More Info" button.

• This opens the Apple System Profiler. Once open, look for "Network Overview" drop down arrow. Under the "Built in" drop down arrow, look for
  - Ethernet address field entry
  - IP field entry

Mac OS 10.2X (pictured below)

This opens the Apple System Profiler. Once open, look for "Network Overview" drop down arrow. Under the "Built in" drop down arrow, look for

- Ethernet address field entry
- IP field entry