76 Bridging
Bridge Filtering
NetBIOS Name Filtering
Introduction The NetBIOS Name Filtering feature compares NetBIOS broadcasts to a “pattern”
that may have a wild card “*” character at the end. For example, if all servers have a
naming convention with the first part of the name the same, for example, “SVR...”,
then you can complete only one entry in the NetBIOS Filter Table to permit
broadcasts to and from the “SVR*” name pattern.
Example of
NetBIOS Name
Filtering
Figure 39 shows an example of how to configure NetBIOS Name Filtering in a
Token Ring Source Rout Bridging application, however the same is true for Et hernet
Transparent Bridging.

Figure 39. NetBIOS Name Filtering Configuration Example

What Is NetBIOS? Network Basic Input Output System (NetBIOS) is a session-level protocol
standardized by IBM that serves as one of the main Application Programming
Interfaces (APIs) for local area network software. Software such as SNA 3270
emulation packages and Lotus Notes operate on top of the NetBIOS layer. Micro soft
LAN Manager uses NetBIOS extensively for identifying clients and servers.
NetBIOS is based on 16-character named “services” that connect to each other.
Servers advertise their implementation of a named service, and clients try to find
servers by transmitting broadcast frames that contain the name of the service they
want.
Boston Branch Office
Bridge
PC
PC
Link 1
LAN LAN
PB S200PB S200
WAN
Bridge
Link 5
HOME_FILE_01BOSTON_FILE_01
Home Office
Bridge Link Parameters
NetBIOS Name Filter Action: Block
NetBIOS Name Filter Table
String Type: ASCII
NetBIOS Name HOME*
Incoming NetBIOS Name
Link Action: PASS
Outgoing NetBIOS Name
Link Action PASS