在OSI七层模型中的会话层提供服务，严格来说是一种API。
NetBIOS主要提供三种类型的服务：
- 名称服务（Name Service）：包括名称注册和名称解析，运行在UDP的137端口，使用
nbtstat -A就是通过137端口进行通信： - 数据报分发服务（Datagram distribution service）：负责发送和接受普通数据报文和广播数据报文，运行在UDP的138端口
- 会话服务（Session service）：负责建立会话连接，运行在TCP的139端口
NetBIOS Name 和 Host Name 的区别：
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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.
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Generally the host name of a Windows computer is based on the NetBIOS name plus the Primary DNS Suffix, which are both set in the System Properties dialog box.
NetBIOS Suffixes（名字的最后一个字符的意义）：
The NetBIOS Suffix, alternately called the NetBIOS End Character (endchar), is the 16th character of a NetBIOS name and indicates service type for the registered name. The number of record types is limited to 255; some commonly used values are:
For unique names:
- 00: Workstation Service (workstation name)
- 03: Windows Messenger service
- 06: Remote Access Service
- 20: File Service (also called Host Record)
- 21: Remote Access Service client
- 1B: Domain Master Browser – Primary Domain Controller for a domain
- 1D: Master Browser
For group names:
- 00: Workstation Service (workgroup/domain name)
- 1C: Domain Controllers for a domain (group record with up to 25 IP addresses)
- 1E: Browser Service Elections
上面nbtstat命令的图中，名称为“P0WD3R<1c>”表示该机器是P0WD3R域中的域控。
在Ubuntu中扫描NetBIOS Name Service：apt-get install nbtscan && nbtscan -vh -f ip.txt
现代的NetBIOS是基于TCP/IP的，所以同样适用于广域网。