Re: Serial Port Sniffing

From: Jeff Woods
Date: Fri Oct 28 2005 - 23:28:39 EST


At 10/28/2005 13:24 -0500, Lee <linuxtwidler@xxxxxxxxx> wrote:
Does anyone have any experience with sniffing data from a serial port w/o the device attached to the serial port or the application having knowledge of this ?

I had found an old kernel module (for 2.2.0, i think) called 'maxty' which would does this. Is there something equivalent for the 2.6.x kernels ?

Or is there a better way to go about doing this?

Don't know about software sniffing but hardware sniffing of RS-232 is relatively simple. Splice in a "Y" cable and configure a serial port of another device to listen. Of course, you'll have to configure the serial port to the same rate, parity and stop bits but that's usually easy. Cut the transmit wire on the sniffer side to ensure nothing outbound succeeds in leaving the sniffer machine. Listening to both sides of the conversation would require two sniffer devices, or at least two serial ports.

--
Jeff Woods <kazrak+kernel@xxxxxxxxxxx>

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