Sniffing a live connection?

[jpritchard]

Hi,

Dont know if this is possible but I thought asking here is worth a try.

I am interested in the data passing to and from my PC.

Using VB (or any other language!) is it possible to read/scan the data passing from a socket that is connected to elsewhere. (and visa versa).

As one side will be connected and the other listening, I dont know if there is a way for a vb app I write to listen to a program already listing on a specific port. Ditto for a app to listen to a sending port connected to elsewhere.

There must be some sort of answer (applcations like netcat, I believe can "front" ports although I think that this can block the communication - I dont want to disrupt! - eg netcat's documentation talks of running over port 139 and this shutting of file sharing - I want to listen)

I am a little out of my depth (my background being SAP & Mainframe) but have tinkered with VB (specifically winsocks) - seems fairly easy to me so far. I dont mind ignoring the objects and writing straight for the API if required. (the vbapi site is great!)


Just for info - this isnt a hacking exercise I am undertaking - I am slightly bemused at the amount of shares on our pcs (work) (it is well known around our business on "how to connect to someone elses C drive")

Also a collegue once connected to me (without me knowing) - using pc-anywhere. I found out our helpdesk was rolling it out without the user confirmation option. (found it/switched it). As I sometimes am involved with fixing our payroll, I dont take kindly to these type of things and wonder whatelse is happening/loaded etc etc.

Hence my asking this question.

Many thanks to anyone who can help,

Cheers, A.J.P.

[JoshT]

You want a Packet Sniffer? Good commercial ones I've used demos of are Commview (about $100) and Eeye's Iris (costs an arm and a leg).

A good free one is Ethereal. www.ethereal.com You'll need the "winpcap" driver and "GTK" libraries to run it.

As far as VB goes, I haven't seen anything that can go that low level, but I'm fairly certain someone could write some dll's in c++ that could be used by VB via API calls, or maybe even a COM wrapper.