This results in each computer in the network having both an IP address and a NetBIOS name corresponding to a ( possibly different ) host name.

The name NetBEUI should have died there, considering that at the time, the NetBIOS implementations by other companies were known simply as NetBIOS regardless of whether they incorporated the API extensions found in that emulator.

Consequently, even today, Microsoft file and printer sharing over Ethernet continues to be called NetBEUI, with the name NetBIOS commonly used only in reference to file and printer sharing over TCP / IP.

In order to start sessions or distribute datagrams, an application must register its NetBIOS name using the name service.

The name service primitives offered by NetBIOS are:

* Add name – registers a NetBIOS name.

* Add group name – registers a NetBIOS " group " name.

* Delete name – un-registers a NetBIOS name or group name.

* Find name – looks up a NetBIOS name on the network.

* Call – opens a session to a remote NetBIOS name.

* Listen – listen for attempts to open a session to a NetBIOS name.

* Send Datagram – send a datagram to a remote NetBIOS name.

The NetBIOS name is 16 ASCII characters, however Microsoft limits the host name to 15 characters and reserves the 16th character as a NetBIOS Suffix.

Today this is usually an IP address ( the NetBIOS name – IP address resolution is often done by either broadcasts or a WINS Server – NetBIOS Name Server ).

The Windows LMHOSTS file provides a NetBIOS name resolution method that can be used for small networks that do not use a WINS server.

** MSKB837391: Exchange Server 2003 and Exchange 2000 Server require NetBIOS name resolution for full functionality

A central role of NetBIOS in Client-Server networks ( and also those networks that have networked peripheral hardware that also predates DNS compatibility ) is to provide name resolution to computers and networked peripherals.

There is also Windows Internet Name Service ( WINS ), which is effectively the same to NetBIOS names as DNS is to domain names.

A specific example of a nuke attack that gained some prominence is the WinNuke, which exploited the vulnerability in the NetBIOS handler in Windows 95.

NetBIOS () is an acronym for Network Basic Input / Output System.

As strictly an API, NetBIOS is not a networking protocol.

The NBT protocol was developed in order to " allow an implementation NetBIOS applications to be built on virtually any type of system where the TCP / IP protocol suite is available ," and to " allow NetBIOS interoperation in the Internet.

Worth noting is the popular confusion between the names NetBIOS and NetBEUI.

In truth, the former is the NetBIOS Frames protocol ( NBF ), and the latter is NetBIOS over TCP / IP ( NBT ).

( Note: SMB, an upper layer, is a service that runs on top of the Session Service and the Datagram service, and is not to be confused as a necessary and integral part of NetBIOS itself.

It is called the NetBIOS Suffix ( read below ) or " resource type ", and is used to tell other applications what type of services the system offers.

Since NetBIOS is handling the error recovery, NACK packets will prompt retransmission of the data packet.

When NetBIOS is run over the TCP / IP protocol, each computer may have multiple " names " — names for the NetBIOS API and another ( or others ) for basic TCP / IP.

Because PC Network only supported up to 80 devices in its most accommodating mode ( baseband ), NetBIOS was itself designed with limited nodes in mind.

In reality, the protocols were supported as a native transport for Windows ' SMB / NetBIOS, and NetWare connectivity required additional installation of an NCP client ( Microsoft provided a basic NetWare client with Windows 95 and later, but it was not automatically installed, and initially only supported NetWare bindery mode ).

NetBIOS was developed in 1983 by Sytek Inc. as an API for software communication over IBM PC Network LAN technology.

As in the case of IBM's token ring, the services of Microsoft's NetBIOS implementation were provided over the IEEE 802. 2 Logical Link Control layer by the NBF protocol.

The session service primitives offered by NetBIOS are:

The datagram service primitives offered by NetBIOS are:

NBF protocol or NetBIOS over IEEE 802. 2 LLC is used by a number of network operating systems released in the 1990s, such as LAN Manager, LAN Server, Windows for Workgroups, Windows 95 and Windows NT.

In addition, to start a session or to send a datagram to a particular host rather than to broadcast the datagram, NBF protocol has to determine the MAC address of the host with a given NetBIOS / NetBEUI name ; this is done by sending a " Name Query " packet, the response to which will have the MAC address of the host sending the response, i. e. the host with that name.

NetBIOS functions by broadcasting services available on a particular host at regular intervals.

These messages are easily blocked by firewalls configured to block packets to the NetBIOS ports 135-139 and 445 as well as unsolicited UDP packets to ports above 1024.

In addition, to start a session or to send a datagram to a particular host rather than to broadcast the datagram, NBT will have to determine the IP address of the host with a given NetBIOS name ; this is done by broadcasting a " Name Query " packet, and / or sending it to the NetBIOS name server.

In order to use the Messenger Service functionality of Windows through the NET SEND command, either by itself or with the use of a third party NetBIOS messaging application, it is recommended that the NetBIOS ports cannot be reached from sources external to the local network.

When the proprietary PC Network hardware was replaced by token ring in IBM's later offerings, backwards compatibility with the NetBIOS application programming interface ( API ) was retained through an optional loadable program module.

According to Sir Dystic, " NBName can disable entire LANs and prevent machines from rejoining them ... nodes on a NetBIOS network infected by the tool will think that their names already are being used by other machines.