LISTEN(1)           Linux Programmer's Manual           LISTEN(1)



NAME
       listen - monitor AX.25 traffic

SYNOPSIS
       listen [-8] [-a] [-c] [-h] [-i] [-p port] [-r] [-t] [-v]

DESCRIPTION
       Listen  uses  SOCK_PACKET  facilities to provide a network
       monitor of all AX.25 traffic heard by  the  system.  Since
       KISS  is implicitly promiscuous no special driver configu-
       rations are needed.

       This version  displays  standard  AX.25,  PE1CHL  extended
       AX.25,  NET/ROM, Rose, ARP, IP, ICMP, TCP and UDP. It also
       displays IP, TCP, ICMP, TCP and  UDP  encapsulated  within
       NET/ROM  frames.  The  program  also displays AX.25 and IP
       encapsulated within an IP frame, but see RFC1326 for  rea-
       sons not to do so.

       Listen  makes an attempt at decoding some of the more com-
       mon routing protocols. RSPF and  RIP  (both  "normal"  and
       G8BPQs  RIP98)  are  traced. JNOS style NET/ROM node polls
       are also displayed.

       Listen can use colors to make the  output  more  readable.
       The  ncurses  library  is  used to accomplish this.  Color
       support defaults to being disabled, and the  -c  parameter
       is used to enable it.

OPTIONS
       -8        Indicates that the terminal is capable of print-
                 ing 8-bit characters. This parameter is required
                 for the -i parameter to work.

       -a        Allow  for  the monitoring of outgoing frames as
                 well as incoming ones.

       -c        Enable color support.

       -h        Dump the data portion of the packet in both hex-
                 adecimal  and  ASCII.  The default is to display
                 data as ASCII only.

       -i        Map IBM codepage 437 characters 128-158 to their
                 ISO-Latin-1  equivalents.   This  is  a hack for
                 scandinavian users. This parameter is only valid
                 when used with the -8 and -c parameters.

       -p port   Monitor only those frames received on a particu-
                 lar port, by default all AX.25 devices are moni-
                 tored.

       -r        Dump  the  data portion in a "readable" fashion,
                 which is more  suitable  for  tracing  plaintext
                 AX.25 traffic. CR-LF conversion is done.

       -t        Displays  a timestamp with each packet received.

       -v        Display the version.

FILES
       /etc/ax25/axports

SEE ALSO
       call(1),   mheard(1),   beacon(1),   ax25(4),   netrom(4),
       rose(4), kissattach(8).


BUGS
       Listen does not validate the checksums of frames that sup-
       port them (ie IP), therefore corrupt frames will  be  dis-
       played with bogus values. The MSS of a TCP frame that con-
       tains that option is not displayed.

AUTHORS
       Alan Cox GW4PTS <alan@cymru.net>
       Jonathan Naylor G4KLX <g4klx@g4klx.demon.co.uk>
       Phil Karn KA9Q <karn@qualcomm.com>
       Heikki Hannikainen OH7LZB <hessu@pspt.fi>



Linux                     27 August 1996                LISTEN(1)
