Trace TCP/IP data

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Robert - 27 Jan 2005 05:50 GMT

I am looking for a program to trace tcp/ip data that flows through my
modem. Analysis of the data would be helpful.

Thanks.

Robert

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D P Schreber - 27 Jan 2005 12:17 GMT

> I am looking for a program to trace tcp/ip data that flows through my
> modem. Analysis of the data would be helpful.

The command line tool tcpdump is included with osx and does this very
well.

If you want one with an X11 gui, try ethereal:

http://sourceforge.net/projects/ethereal/

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rccharles@my-deja.com - 29 Jan 2005 17:27 GMT

I tried to use tcpdump from the command and from the applescript. I
believe that I need to specify the interface device. I tried sudo
tcpdump -i cu.modem but tcpdump: BIOCSETIF: cu.modem: Device not
configured. How would I find the unix name for the modem?

Robert

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D P Schreber - 29 Jan 2005 17:45 GMT

> I tried to use tcpdump from the command and from the applescript. I
> believe that I need to specify the interface device. I tried sudo
> tcpdump -i cu.modem but tcpdump: BIOCSETIF: cu.modem: Device not
> configured. How would I find the unix name for the modem?

Run ifconfig when the modem is connected, the device will be listed.
I've never used dialup in osx but it's probably something like ppp0.

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Matt Broughton - 30 Jan 2005 01:05 GMT

> > I tried to use tcpdump from the command and from the applescript. I
> > believe that I need to specify the interface device. I tried sudo
[quoted text clipped - 3 lines]
> Run ifconfig when the modem is connected, the device will be listed.
> I've never used dialup in osx but it's probably something like ppp0.

That is exactly the right interface designation:

sudo tcpdump -i ppp0

Signature

Matt Broughton
Only relatives are absolute.

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Gnarlodious - 27 Jan 2005 15:49 GMT

Entity Robert spoke thus:

> I am looking for a program to trace tcp/ip data that flows through my
> modem. Analysis of the data would be helpful.

I've uploaded my script " AirportUsers" to:
<http://Gnarlodious.com/Apple/AppleScript/Scripts/AirportUsers/AirportUsers.
html>

It offers rudimentary control of the tcpdump command.
Works with Airport Extreme, not sure about other routers. Reports are
appreciated, I may change the name of it.

Launch the script and it starts tcpdump logging. After a while, click the
dock icon and it reports the IP of active machines on the router. You can
then choose to open the log file to see the details. More analysis is needed
but it should get you going.

To end logging bring Terminal to the front and press "ctrl-c"

-- Gnarlie's Applescript page:
http://Gnarlodious.com/Apple/AppleScript/

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Mac Forum / General / Networking / January 2005

Trace TCP/IP data