Cisco Systems BC-109 Manual De Usuario

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Secure the SRB Network
BC-134
Bridging and IBM Networking Configuration Guide
The NetBIOS station access list contains the station name to match, along with a permit or deny 
condition. You must assign the name of the access list to a station or set of stations on the network. 
To assign a station access list name, use the following command in global configuration mode:
When filtering by station name, you can choose to filter either incoming or outgoing messages on 
the interface. To specify the direction, use one of the following commands in interface configuration 
mode:
Configure NetBIOS Access Filters Using a Byte Offset 
To configure access filters you must do the following:
Step 1
Assign a byte offset access list name.
Step 2
Specify the direction of the message to be filtered on the interface.
Keep the following notes in mind while configuring access filters using a byte offset:
When an access list entry has an offset plus the length of the pattern that is larger than the packet’s 
length, the entry will not make a match for that packet.
Because these access lists allow arbitrary byte offsets into packets, these access filters can have 
a significant impact on the amount of packets per second transiting across the bridge. They 
should be used only when situations absolutely dictate their use.
The NetBIOS byte offset access list contains a series of offsets and hexadecimal patterns with which 
to match byte offsets in NetBIOS packets. To assign a byte offset access list name, use the following 
command in global configuration mode:
Note
Using NetBIOS Byte Offset access filters disables the autonomous or fast switching of 
source-route bridging frames.
When filtering by byte offset, you can filter either incoming or outgoing messages on the interface. 
To specify the direction, use one of the following commands in interface configuration mode:
Command
Purpose
netbios access-list host name {permit | denypattern
Assign the name of an access list to a 
station or set of stations on the network.
Command
Purpose
netbios input-access-filter host name
Define an access list filter for incoming 
messages.
netbios output-access-filter host name
Define an access list filter for outgoing 
messages.
Command
Purpose
netbios access-list bytes name {permit | denyoffset 
pattern
Define the byte offsets and patterns 
within NetBIOS messages to match 
with access list parameters.
Command
Purpose
netbios input-access-filter bytes name
Specify a byte-based access filter on 
incoming messages.