25.2 Background Information

Since the introduction of MS Windows 2000, it is possible to run MS Windows networking without the use of NetBIOS over TCP/IP. NetBIOS over TCP/IP uses UDP port 137 for NetBIOS name resolution and uses TCP port 139 for NetBIOS session services. When NetBIOS over TCP/IP is disabled on MS Windows 2000 and later clients , then only the TCP port 445 will be used and the UDP port 137 and TCP port 139 will not.

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When using Windows 2000 or later clients, if NetBIOS over TCP/IP is not disabled, then the client will use UDP port 137 (NetBIOS Name Service, also known as the Windows Internet Name Service or WINS), TCP port 139 and TCP port 445 (for actual file and print traffic).

When NetBIOS over TCP/IP is disabled, the use of DNS is essential. Most installations that disable NetBIOS over TCP/IP today use MS Active Directory Service (ADS). ADS requires Dynamic DNS with Service Resource Records (SRV RR) and with Incremental Zone Transfers (IXFR). Use of DHCP with ADS is recommended as a further means of maintaining central control over the client workstation network configuration.