@@@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 configurations 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 reasons not to do so.

@@@Listen@@@ makes an attempt at decoding some of the more common 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 printing 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 hexadecimal 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 particular port, by default all AX.25 devices are monitored.

-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  Don't print a timestamp on each dump line.

-tt Print an unformatted timestamp on each dump line.

-ttt
    Print a delta (micro-second resolution) between current and previous line on each dump line.

-tttt
    Print a timestamp in default format proceeded by date on each dump line.

-ttttt
    Print a delta (micro-second resolution) between current and first line on each dump line.

-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 support them (ie IP), therefore corrupt frames will be displayed with bogus values. The MSS of a TCP frame that contains 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 <oh7lzb@sral.fi>
Scott Miller N1VG <scott@opentrac.org>