Specifications

© 2006 Cisco Systems, Inc.
All rights reserved.
Product Features 2-161
NAM / Traffic Analyzer v3.5 Tutorial
© 2006 Cisco Systems, Inc. All rights reserved.
Product Features 2-161
NAM / Traffic Analyzer v3.5 Tutorial
Packet Capture and Decode
Custom Display Filters
Packet Capture and Decode
Custom Display Filters
If you do not want to filter by
protocol, choose ALL from the
protocol pull-down list.
If you do not want to filter by
protocol, choose ALL from the
protocol pull-down list.
Enter the data string or pattern
that you want to filter on.
Remember this must be
written in hexadecimal.
Enter the data string or pattern
that you want to filter on.
Remember this must be
written in hexadecimal.
The Offset and Base options
instruct the filter where in the
packet to begin searching for
the data pattern you defined
above.
The Offset and Base options
instruct the filter where in the
packet to begin searching for
the data pattern you defined
above.
You can use Boolean logic
to define more complex
filters.
You can use Boolean logic
to define more complex
filters.
If desired, enter addresses as
part of the filter definition.
If desired, enter addresses as
part of the filter definition.
Capture > Custom Filters > Display Filters
Creating Custom Display Filters
You can apply the same powerful filter control over captured packets as you can over the capture process
by creating your own display filter by selecting the Capture > Custom Filters > Display Filters task. You
have the same option for searching for data patterns found either in the protocol headers or in the data field
of the packet. To use this feature, you need to identify a few things:
• Again, you need to write the data pattern you are looking for in hexadecimal.
• You also need to tell it where to begin the data string search. If you choose absolute, you are telling
the filter to begin looking at the first bit of the packet. If you choose protocol, you are instructing the
filter to begin looking at the first bit of the protocol header.
Another feature unique to this filter is the option to use Boolean logic to define more complex Decode Filters,
using the Filter Expression field. Defining your own custom filters is a very powerful and complex tool that
requires thought and preparation. Refer to the Settings chapter of the User Guide for more detailed
information and instructions on defining custom filters.