listen(1)

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

6       listen - monitor AX.25 traffic
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SYNOPSIS

9       listen [-8] [-a] [-c] [-h] [-i] [-p port] [-r] [-t..] [-v]
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DESCRIPTION

12       Listen  uses SOCK_PACKET facilities to provide a network monitor of all
13       AX.25 traffic heard by the system. Since KISS is implicitly promiscuous
14       no special driver configurations are needed.
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16       This  version  displays standard AX.25, PE1CHL extended AX.25, NET/ROM,
17       Rose, ARP, IP, ICMP, TCP and UDP. It also displays IP, TCP,  ICMP,  TCP
18       and  UDP  encapsulated within NET/ROM frames. The program also displays
19       AX.25 and IP encapsulated within an IP frame, but see RFC1326 for  rea‐
20       sons not to do so.
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22       Listen  makes  an  attempt  at decoding some of the more common routing
23       protocols. RSPF and RIP (both “normal” and G8BPQs  RIP98)  are  traced.
24       JNOS style NET/ROM node polls are also displayed.
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26       Listen  can  use  colors  to make the output more readable. The ncurses
27       library is used to accomplish this.  Color support  defaults  to  being
28       disabled, and the -c parameter is used to enable it.
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OPTIONS

31       -8        Indicates  that  the  terminal  is  capable of printing 8-bit
32                 characters. This parameter is required for the  -i  parameter
33                 to work.
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35       -a        Allow for the monitoring of outgoing frames as well as incom‐
36                 ing ones.
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38       -c        Enable color support.
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40       -h        Dump the data portion of the packet in both  hexadecimal  and
41                 ASCII. The default is to display data as ASCII only.
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43       -i        Map  IBM codepage 437 characters 128-158 to their ISO-Latin-1
44                 equivalents.  This is a hack  for  scandinavian  users.  This
45                 parameter  is only valid when used with the -8 and -c parame‐
46                 ters.
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48       -p port   Monitor only those frames received on a particular  port,  by
49                 default all AX.25 devices are monitored.
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51       -r        Dump  the data portion in a "readable" fashion, which is more
52                 suitable for tracing plaintext AX.25 traffic.  CR-LF  conver‐
53                 sion is done.
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55       -t        Don't print a timestamp on each dump line.
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57       -tt       Print an unformatted timestamp on each dump line.
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59       -ttt      Print  a  delta (micro-second resolution) between current and
60                 previous line on each dump line.
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62       -tttt     Print a timestamp in default format proceeded  by   date   on
63                 each dump line.
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65       -ttttt    Print  a  delta   (micro-second  resolution)  between current
66                 and first line on each dump line.
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68       -v        Display the version.
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FILES

71       /etc/ax25/axports
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BUGS

78       Listen  does not validate the checksums of frames that support them (ie
79       IP), therefore corrupt frames will be displayed with bogus values.  The
80       MSS of a TCP frame that contains that option is not displayed.
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AUTHORS

83       Alan Cox GW4PTS <alan@cymru.net>
84       Jonathan Naylor G4KLX <g4klx@g4klx.demon.co.uk>
85       Phil Karn KA9Q <karn@qualcomm.com>
86       Heikki Hannikainen OH7LZB <oh7lzb@sral.fi>
87       Scott Miller N1VG <scott@opentrac.org>
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91Linux                           27 August 1996                       LISTEN(1)