Ethernet Address Lookup

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Label of a router with MAC addresses for and modules A media access control address ( MAC address) of a device is a assigned to a (NIC). For communications within a network segment, it is used as a for most network technologies, including,. Within the (OSI) model, MAC addresses are used in the protocol sublayer of the. As typically represented, MAC addresses are recognizable as six groups of two digits, separated by hyphens, colons, or no separator. A MAC address may be referred to as the burned-in address, and is also known as an Ethernet hardware address, hardware address, and physical address.

A with multiple NICs must have a unique MAC address for each. Sophisticated such as a or may require one or more permanently assigned MAC addresses. MAC addresses are most often assigned by the manufacturer of network interface cards. Each is stored in hardware, such as the card's or by a mechanism. A MAC address typically includes the manufacturer's (OUI). MAC addresses are formed according to the principles of two numbering spaces based on Extended Unique Identifiers (EUI) managed by the (IEEE): EUI-48, which replaces the obsolete term MAC-48, and EUI-64. Diagram showing the structure of a 48-bit MAC address, explicitly showing the positions of the / bit and the OUI/local address type bit.

The original MAC address comes from the original Ethernet addressing scheme. This address space contains potentially 2 48 or 281,474,976,710,656 possible MAC addresses. The manages allocation of MAC addresses, originally known as MAC-48 and which it now refers to as EUI-48 identifiers. The IEEE has a target lifetime of 100 years (until 2080) for applications using EUI-48 space and restricts applications accordingly. The IEEE encourages adoption of the more plentiful EUI-64 for non-Ethernet applications. The distinction between EUI-48 and MAC-48 identifiers is in name and application only.

MAC-48 was used to address hardware interfaces within existing 802-based networking applications; EUI-48 is now used for 802-based networking and is also used to identify other devices and software, for example. The IEEE now considers MAC-48 to be an obsolete term.

EUI-48 is now used in all cases. In addition, the EUI-64 numbering system originally encompassed both MAC-48 and EUI-48 identifiers by a simple translation mechanism. These translations have since been deprecated. — one of the most prominent standards that uses a Modified EUI-64 — treats MAC-48 as EUI-48 instead (as it is chosen from the same address pool) and toggles the U/L bit (as this makes it easier to type locally assigned IPv6 addresses based on the Modified EUI-64).

An Ethernet or Wireless hardware address is a 6-byte hexadecimal number; for example: 080007A9B2FC. Each byte is written as two hexadecimal digits, so there are twelve hexadecimal digits; each hex digit is a number from 0-9 or a letter from A-F. The letters A-F may be uppercase or lowercase.

This results in extending MAC addresses (such as IEEE 802 MAC address) to Modified EUI-64 using only FF-FE (and never FF-FF) and with the U/L bit inverted. An (IAB) is an inactive registry activity which has been replaced by the MA-S (MA-S was previously named ) registry product as of January 1, 2014. The IAB uses a OUI from MA-L (MA-L registry was previously named OUI registry, the term OUI is still in use, but not for calling a registry ) belonging to the IEEE Registration Authority, concatenated with 12 additional IEEE-provided bits (for a total of 36 bits), leaving only 12 bits for the IAB owner to assign to their (up to 4096) individual devices. An IAB is ideal for organizations requiring not more than 4096 unique 48-bit numbers (EUI-48).

Unlike an OUI, which allows the assignee to assign values in various different number spaces (for example, EUI-48, EUI-64, and the various context-dependent identifier number spaces), the Individual Address Block could only be used to assign EUI-48 identifiers. All other potential uses based on the OUI from which the IABs are allocated are reserved, and remain the property of the IEEE Registration Authority. It should also be noted that, between 2007 and September 2012, the OUI value 00:50:C2 was used for IAB assignments. After September 2012, the value 40:D8:55 was used.

The owners of an already assigned IAB may continue to use the assignment. There is another registry which is called MA-M (MAC Addresses - Medium). The MA-M assignment block provides both 2 20 EUI-48 identifiers and 2 36 EUI-64 identifiers (that means first 28 bits are IEEE assigned bits). The first 24-bits of the assigned MA-M block are an OUI assigned to IEEE that will not be reassigned.

Universal vs. Local Addresses can either be universally administered addresses (UAA) or locally administered addresses (LAA). A universally administered address is uniquely assigned to a device by its manufacturer. The first three octets (in transmission order) identify the organization that issued the identifier and are known as the (OUI). The remainder of the address (three octets for EUI-48 or five for EUI-64) are assigned by that organization in nearly any manner they please, subject to the constraint of uniqueness.

A locally administered address is assigned to a device by a network administrator, overriding the burned-in address. Universally administered and locally administered addresses are distinguished by setting the second- of the first octet of the address.

This bit is also referred to as the U/L bit, short for Universal/Local, which identifies how the address is administered. If the bit is 0, the address is universally administered. If it is 1, the address is locally administered. In the example address 06-00-00-00-00-00 the first octet is 06 (hex), the binary form of which is 00000110, where the second-least-significant bit is 1.

Therefore, it is a locally administered address. Another example that uses locally administered addresses is the protocol. The MAC address of the Ethernet interface is changed by the DECnet software to be AA-00-04-00-XX-YY where XX-YY reflects the DECnet network address xx.yy of the host. This eliminates the need for an address resolution protocol since the MAC address for any DECnet host can be simply determined. Multicast When the least significant bit of an address's first octet is 0 (zero), the is meant to reach only one receiving. This type of transmission is called.

A unicast frame is transmitted to all nodes within the. In a modern wired setting the collision domain usually is the length of the Ethernet cable between two network cards. In a wireless setting, the collision domain is all receivers that can detect a given wireless signal. If a does not know which port leads to a given MAC address, the switch will forward a unicast frame to all of its ports (except the originating port), an action known as. Only the node with the matching hardware MAC address will accept the frame; network frames with non-matching MAC-addresses are ignored, unless the device is in.

If the least significant bit of the first octet is set to 1, the frame will still be sent only once; however, NICs will choose to accept it based on criteria other than the matching of a MAC address: for example, based on a configurable list of accepted multicast MAC addresses. This is called addressing. The IEEE has built in several special address types to allow more than one to be addressed at one time:. Packets sent to the, all one bits, are received by all stations on a local area network. In the broadcast address would be FF:FF:FF:FF:FF:FF. A broadcast frame is and is forwarded to and accepted by all other nodes. Packets sent to a are received by all stations on a LAN that have been configured to receive packets sent to that address.

Functional addresses identify one or more Token Ring NICs that provide a particular service, defined in. These are all examples of group addresses, as opposed to individual addresses; the least significant bit of the first octet of a MAC address distinguishes individual addresses from group addresses. That bit is set to 0 in individual addresses and set to 1 in group addresses. Group addresses, like individual addresses, can be universally administered or locally administered. Applications. This section possibly contains. Please by the claims made and adding.

Statements consisting only of original research should be removed. ( January 2017) The following network technologies use the EUI-48 identifier format:. Ethernet. wireless networks. IEEE 802.5.

most other IEEE 802 networks. (FDDI).

(ATM), switched virtual connections only, as part of an. and (as part of a ). The standard, which provides a way to create a high-speed (up to 1 gigabit/s) using existing home wiring (, phone lines and ).

The G.hn Application Protocol Convergence (APC) layer accepts Ethernet frames that use the EUI-48 format and encapsulates them into G.hn Service Data Units (MSDUs). Every device that connects to an IEEE 802 network (such as Ethernet and WiFi) has a EUI-48 address. Common networked consumer devices such as PCs, smartphones and tablet computers use EUI-48 addresses. EUI-64 identifiers are used in:. (FireWire). (Modified EUI-64 as the least-significant 64 bits of a unicast network address or link-local address when stateless address autoconfiguration is used.).

/ / wireless personal-area networks Usage in hosts On broadcast networks, such as Ethernet, the MAC address is expected to uniquely identify each on that segment and allows frames to be marked for specific hosts. It thus forms the basis of most of the (OSI ) networking upon which upper layer protocols rely to produce complex, functioning networks. Many network interfaces support changing their MAC address. On most -like systems, the command utility may be used to remove and add link address aliases.

For instance, the active ifconfig directive may be used on to specify which of the attached addresses to activate. Hence, various configuration scripts and utilities permit the randomization of the MAC address at the time of booting or before establishing a network connection. Changing MAC addresses is necessary in.

In, this is practiced in exploiting security vulnerabilities of a computer system. Some modern operating systems, such as Apple iOS and Android, especially in mobile devices, are designed to randomize the assignment of a MAC address to network interface when scanning for wireless access points to avert tracking systems. In (IP) networks, the MAC address of an interface corresponding to an may be queried with the (ARP) for and the (NDP) for, relating Layer 3 addresses to Layer 2 addresses. Tracking.

Main article: According to, the US has a system that tracks the movements of mobile devices in a city by monitoring MAC addresses. To avert this practice, has started using random MAC addresses in devices while scanning for networks. Other vendors followed quickly.

MAC address randomization during scanning was added in Android starting from version 6.0, Windows 10, and Linux kernel 3.18. The actual implementations of the MAC address randomization technique vary largely in different devices. Moreover, various flaws and shortcomings in these implementations may allow an attacker to track a device even if its MAC address is changed, for instance its probe requests' other elements, or their timing.

If random MAC addresses are not used, researchers have confirmed that it is possible to link a real identity to a particular wireless MAC address. Using in -hidden mode , a mobile wireless device may not only disclose its own MAC address when traveling, but even the MAC addresses associated to SSIDs the device has already connected to, if they are configured to send these as part of probe request packets. Alternative modes to prevent this include configuring access points to be either in beacon-broadcasting mode, or probe-response with SSID mode. In these modes, probe requests may be unnecessary, or sent in broadcast mode without disclosing the identity of previously-known networks.

Notational conventions The standard format for printing EUI-48 addresses in human-friendly form is six groups of two digits, separated by hyphens ( -) in transmission order (e.g. This form is also commonly used for EUI-64 (e.g. Other conventions include six groups of two hexadecimal digits separated by colons (:) (e.g.

01:23:45:67:89:AB), and three groups of four hexadecimal digits separated by dots (.) (e.g. 0123.4567.89AB); again in transmission order. Bit-reversed notation The standard notation, also called canonical format, for MAC addresses is written in transmission order with the least significant bit of each byte transmitted first, and is used in the output of the ifconfig, and commands, for example. However, since (Ethernet) and (Token Bus) send the bytes (octets) over the wire, left-to-right, with least significant bit in each byte first, while (Token Ring) and (FDDI) send the bytes over the wire with the most significant bit first, confusion may arise when an address in the latter scenario is represented with bits reversed from the canonical representation. For example, an address in canonical form 12-34-56-78-9A-BC would be transmitted over the wire as bits 010110 000101 in the standard transmission order (least significant bit first).

But for Token Ring networks, it would be transmitted as bits 000010 011100 in most-significant-bit first order. The latter might be incorrectly displayed as 48-2C-6A-1E-59-3D. This is referred to as bit-reversed order, non-canonical form, MSB format, IBM format, or Token Ring format, as explained in. See also., which may spoof another device's MAC address during certain periods. Notes.

A Media Access Control (MAC) address is a unique numeric identifier used to distinguish a device from others on a network. The address is assigned by the manufacturer, for Ethernet and Wi-Fi cards. Your device therefore is likely to have two MAC addresses.

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Windows

Get your computer's Wired or Wireless MAC address from the Command Prompt Screen:

  1. Select the Start button.
  2. Type command in the search box (Start->Run for Windows XP) and press Enter.
  3. *At the Command Prompt, type *ipconfig /all Note: Be sure to put a space between ipconfig and /all!
  4. Press Enter to list the connection information for your wired and/or wireless connections.
  5. To find the Physical Address for your connection:
    • The wired physical address will be listed under Ethernet adapter Local Area Connection
    • The wireless physical address will be listed under Ethernet adapter Wireless Network Connection
  6. Write down or copy/paste the addresses for future reference.

Copy this information from the command prompt screen into a notepad document:

  1. Right-click anywhere in the command prompt window and choose Select All.
  2. Press Enter to copy the text from the Command Prompt screen.
  3. Open up Notepad (Start->All Programs->Accessories->Notepad).
  4. Right-click and choose Paste to put the information into the document.
  5. Save and Print the document and keep it with your important papers.

Mac (OSX)

To get your computer's Wired or Wireless MAC address from the Terminal Screen:

  1. Locate and open Terminal from Applications->Utilities->Terminal.
  2. At the Terminal Prompt, type ifconfig and press Enter. This will list all of your network settings, including the physical addresses of your wired and wireless hardware.
  3. To find the Physical Address for your connection:
    > The wired physical address will be listed under en0
    > The wireless physical address will be listed under en1
  4. Write down or copy/paste the addresses into a document for future reference. You can also directly print it by going to Shell->Print. Keep this document with your important papers.

Apple TV

  • On the box: Look for the Wireless ID near the UPC label
  • On the Apple TV: Go to Menu > Settings > About and look for the Wireless ID

Chromecast

PLEASE NOTE that Chromecasts do NOT currently work at Brown. Sorry!

Lookup

In most cases, it will be listed on the page which asks you to select a wireless network (below are screenshots for Android and Mac). On a PC, you may have to click Settings to get to this page.

Amazon Echo

  1. Download the Amazon Alexa app to your phone or computer and sign in with your Amazon account.
  2. Connect to the wireless network transmitted by your Echo device.
  3. The wireless MAC address for your Echo can be found at the bottom of the Echo Setup screen in the Alexa app.

PlayStation 2

  1. Install the network adapter given in the installation guide or on the PlayStation 2 Network Adapter Web site. Once you have the network adapter installed you are ready to begin the ISP Setup process.
  2. Power up the PlayStation 2 and load the Network Adaptor Startup Disc.
  3. Once it has loaded, select ISP Setup and press X.
  4. The ISP SETUP will begin to load, and you will be presented with a license agreement. Select Agree and press X to continue.
  5. For connection type, choose Local Area Network (LAN) and press X to continue.
  6. Select Automatic Configuration and press X to continue.
  7. At the connection test screen, select Advanced and press X to continue.
  8. At the Advanced Broadband Settings screen, make sure Automatic is selected. While you are at this screen, make note of the MAC Address at the bottom. You will need this number to register your game console.

Playstation 3

  1. Power up the PlayStation 3 without any disc in the drive.
  2. Once the PlayStation 3 operating system has loaded, select 'Settings.'
  3. Once you are in 'Settings' select 'Network Settings.'
  4. When the 'Network Settings' list appears, select the first option which is titled 'Settings and Connection Status List.'
  5. The physical address will be listed under 'MAC Address'

Samsung Smart TV

  1. Go to your TV's menu and choose Network > Network Settings
  2. Choose Wireless for your connection type
  3. Choose to connect to the Brown-Guest network
  4. On some Smart TVs, you will see the MAC Address on the next screen.
    If it is not displayed, go back to the menu and choose Network > Network Status.

Wii

The Nintendo Wii is unable to access the Brown network via wireless connection and will require the purchase and use of the Wii LAN Adapter.

  1. When at the Wii menu screen, click the Wii icon in the lower left corner.
  2. Select Wii Settings.
  3. Click the arrow on the right side of the screen to advance to the next page of settings.
  4. Select Internet.
  5. Select Console Information.
  6. The MAC address for your console will be displayed under the LAN Adapter MAC Address listing(the second line).

Xbox

  1. Insert your Xbox Live DVD in the drive. The software will automatically run and update the Xbox dashboard to show the Xbox Live option. Once this is complete, eject the CD and make sure you have your network cable plugged into your Xbox and in the network port. Open the Settings menu.
  2. From Settings, go to Network Settings.
  3. Within the Network Settings Menu, go to IP Addresses.
  4. Once in the IP Addresses Menu, be sure the configuration is set to Automatic.
  5. Press B and go back to the Network Settings menu, then go to DNS Servers.
  6. Once in the DNS Servers Menu, be sure the configuration is set to Automatic.
  7. Press B and go back to the Network Settings menu, there you will then see the MAC address in the lower right hand part of the screen. Write this MAC address down somewhere.

Xbox One

If you are able to reach the main menu on your Xbox, follow the steps below to locate the wired MAC address of your console.

  1. If you are signed into your profile, navigate to My Games & Apps. **Skip this step if you are not signed into a profile.
  2. From there, select Settings.
  3. In the settings pane, select Network.
  4. Select Advanced Settings.
  5. Record the Wired MAC address on this screen. It should be in the format '00:00:00:00:00:00.'

Xbox 360

  1. Go to the System area of the Xbox Dashboard and select Network Settings.
  2. Select Edit Settings.
  3. Under Basic Settings, check to make sure the IP Settings is on Automatic.
  4. Now go to Additional Settings, select Advanced Settings.
  5. At the bottom of this screen you'll see a heading called Wired MAC Address.

Testing your Xbox Live Connection

  1. Once you have registered your Xbox 360 with the BGSU network, you can test your Xbox Live Connection. Go to the System area of the Xbox Dashboard and select Network Settings. From this menu then select 'Test Xbox Live Connection'.
  2. The next screen will warn you that testing your network connection will sign everyone out. Select 'Yes' to continue.
  3. Testing of all Xbox Live connection will then take place.
  4. To begin using your Xbox Live connection, Go to the Xbox Live area of the Xbox Dashboard and select the graphic that reads 'Xbox Live'.