
trace [<iface> [off | <btio>]

     Controls packet tracing by the interface drivers. Specific bits
enable  tracing  of the various interfaces and the amount of
information produced.  Tracing is controlled on a per-interface basis;
without arguments, 'trace' gives a list of all defined interfaces and
their tracing status.  Output can be limited to a single interface by
specifying it, and the control flags can be change by specifying them
as well.

     The flags are given as a hexadecimal number which is interpreted
as follows:

B    - Broadcast filter flag. If set, only packets specifically
       addressed to this node will be traced; broadcast packets will
       not be displayed.
T    - Controls type of tracing:
0    - Protocol headers are decoded, but data is not displayed
1    - Protocol headers are decoded, and data (but not the headers
       themselves) are displayed  as ASCII characters, 64 characters/line.
       Unprintable characters are displayed as periods.
2    - Protocol headers are decoded, and the entire packet (headers AND
       data) is also displayed  in hexadecimal and ASCII, 16 characters per
       line.
I    - Enable tracing of input packets if 1, disable if 0
O    - Enable tracing of output packets if 1, disable if 0


          Example:     # Trace all incoming packets on port1 and display with
                       # headers
                       trace port1 0111


