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Discover which company built a networked interface by MAC Address. Several formats accepted: 00-1C-23-59-5A-92, 001c23595a92, 00:1C:23:59:5A:92.
Partial searches are accepted: 001c, 2359:92. Uses several databases including NMAP, IEEE Official List, and more. Never know what else may show up;)MAC addressA media access control address ( MAC address) is a assigned to for communications on the physical network segment.
MAC addresses are used as a for most network technologies, including. Logically, MAC addresses are used in the protocol sublayer of the.MAC addresses are most often assigned by the manufacturer of a (NIC) and are stored in its hardware, such as the card's or some other mechanism. If assigned by the manufacturer, a MAC address usually encodes the manufacturer's registered identification number and may be referred to as the burned-in address ( BIA). It may also be known as an Ethernet hardware address ( EHA), hardware address or physical address. This can be contrasted to a programmed address, where the host device issues commands to the NIC to use an arbitrary address.A may have multiple NICs and each must have one unique MAC address per NIC.MAC addresses are formed according to the rules of one of three numbering name spaces managed by the (IEEE): MAC-48, EUI-48, and EUI-64. The IEEE claims on the names EUI-48 and EUI-64, in which EUI is an abbreviation for Extended Unique Identifier.
Notational conventionsThe standard (IEEE 802) format for printing MAC-48 addresses in human-friendly form is six groups of two digits, separated by hyphens ( -) or colons (:), in transmission order (e.g. 01-23-45-67-89-ab or 01:23:45:67:89:ab ). This form is also commonly used for EUI-64.
Another convention used by networking equipment uses three groups of four hexadecimal digits separated by dots (.) (e.g. 0123.4567.89ab ), again in transmission order. Address detailsThe original IEEE 802 MAC address comes from the original Ethernet addressing scheme.
This 48-bit address space contains potentially 248 or 281,474,976,710,656 possible MAC addresses.All three numbering systems use the same format and differ only in the length of the identifier. Addresses can either be universally administered addresses or locally administered addresses. A universally administered address is uniquely assigned to a device by its manufacturer.
The first three (in transmission order) identify the organization that issued the identifier and are known as the (OUI). The following three (MAC-48 and EUI-48) or five (EUI-64) octets are assigned by that organization in nearly any manner they please, subject to the constraint of uniqueness. The IEEE has a target lifetime of 100 years for applications using MAC-48 space, but encourages adoption of EUI-64s instead. A locally administered address is assigned to a device by a network administrator, overriding the burned-in address. Locally administered addresses do not contain OUIs.Universally administered and locally administered addresses are distinguished by setting the second- of the most significant byte 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 most significant byte 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. Consequently, this bit is 0 in all OUIs.If the least significant bit of the most significant octet of an address is set to 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, which typically ends at the nearest. A switch will forward a unicast frame through all of its ports (except for the port that originated the frame) if the switch has no knowledge of which port leads to that MAC address, or just to the proper port if it does have knowledge. 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 most significant address 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 following technologies use the MAC-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 MAC-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 MAC-48 address. Common consumer devices to use MAC-48 include every PC, iPhone, iPad, and Android-based devices.The distinction between EUI-48 and MAC-48 identifiers is purely nominal: MAC-48 is used for network hardware; EUI-48 is used to identify other devices and software. (Thus, by definition, an EUI-48 is not in fact a 'MAC address', although it is syntactically indistinguishable from one and assigned from the same numbering space.)The IEEE now considers the label MAC-48 to be an obsolete term, previously used to refer to a specific type of EUI-48 identifier used to address hardware interfaces within existing 802-based networking applications, and thus not to be used in the future. Instead, the proprietary term EUI-48 should be used for this purpose.The EUI-48 is expected to have its address space exhausted by the year 2100.EUI-64 identifiers are used in:. (Modified EUI-64 as the least-significant 64 bits of a unicast network address or link-local address when stateless autoconfiguration is used). / / wireless personal-area networksThe 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.In addition, the EUI-64 numbering system encompasses both MAC-48 and EUI-48 identifiers by a simple translation mechanism. To convert a MAC-48 into an EUI-64, copy the OUI, append the two octets FF-FF and then copy the organization-specified extension identifier. To convert an EUI-48 into an EUI-64, the same process is used, but the sequence inserted is FF-FE. In both cases, the process can be trivially reversed when necessary. Organizations issuing EUI-64s are cautioned against issuing identifiers that could be confused with these forms.
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The IEEE policy is to discourage new uses of 48-bit identifiers in favor of the EUI-64 system.IPv6 — 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). 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. Individual address blockAn is a 24-bit managed by the IEEE Registration Authority, followed by 12 IEEE-provided bits (identifying the organization), and 12 bits for the owner to assign to individual devices. An IAB is ideal for organizations requiring fewer than 4097 unique 48-bit numbers (EUI-48). Mac Address Usage in hostsAlthough intended to be a permanent and globally unique identification, it is possible to change the MAC address on most modern hardware.
Changing MAC addresses is necessary in. It can also be used in the process of exploiting security vulnerabilities. This is called.A host cannot determine from the MAC address of another host whether that host is on the same link as the sending host, or on a network segment to that network segment.In networks, the MAC address of an interface can be queried given the using the (ARP) for Version 4 or the (NDP) for IPv6. In this way, ARP or NDP is used to translate IP addresses ( layer 3) into Ethernet MAC addresses (OSI layer 2). On broadcast networks, such as Ethernet, the MAC address uniquely identifies 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.
Mac Address Usage in switchesLayer 2 switches use MAC addresses to restrict packet transmission to the intended recipient. However, the effect is not immediate. Bit-reversed notationThe standard notation, also called canonical format, for MAC addresses is written in transmission bit order with the least significant bit transmitted first, as seen in the output of the // command, 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 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.
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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.
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Canonical form is generally preferred, and used by all modern implementations.When the first switches supporting both Token Ring and Ethernet came out, some did not distinguish between canonical form and non-canonical form and so did not reverse MAC address bits as required. This led to cases of duplicate MAC addresses in the field. See also. or standard alternative VRRP, which allows multiple routers to share one and MAC address to provide router redundancy.
The project has an open source alternative, the Common Address Redundancy Protocol. On, has a CLUSTERIP target., another endpoint addressing scheme., which may 'take over' another device's MAC address during certain periodsReferences. The Institute of Electrical and Electronics Engineers, Inc. 'The universal administration of LAN MAC addresses began with the Xerox Corporation administering Block Identifiers (Block IDs) for Ethernet addresses.' IEEE-SA. 'IANA Considerations and IETF Protocol Usage for IEEE 802 Parameters'.
September 2008. IEEE-RA.External links. 's.