LAN monitoring

Hi there I am looking for some sort of a way to monitor my LAN in our hostel.They are a lot of problems arising and i am hoping to get to know about some sort of a software that could detect certain words and trace the ip of the sys from which it was typed.I hope u get the picture…Can i get any help??? :eek:

For what, www access?
//Danne

No…I m not intrested in www stuff.I m stuck in a hell of a prob…Some is blackmailing me and i douth its in the hostel and he/she is using an id to blackmail me.I need some thing dat will monitor certain words which i tell to scan and will net me knw…Got the picture?

Scan what?
Unless you know what your looking for tcpdump is your best bet.
http://www.tcpdump.org/
Yes, its hard to use and you need to have knowledge regarding TCP/IP and networks in general to find it useful.
//Danne

Yes i know abt it but like u said its hard and i dont knw wat to do in it…Any way wat i was looking for was a software that can help me as such:-
The person who is blackmailing me is using a certain id, so wat i want is when ever he is typing his id which ofcourse i know and will hav it feed into the software will trigger and will let me knw through an ip trace.
Let me giv u a scenario of wat i want.
I hav dat software installed and its working and now that unknown person is using his sys and logs on to his id through which he blackmails me.Now the moment he uses the his id words the software dat i hav installed will catch these words and let me know so dat i can detect dat person.
If this is not possible then tell me another alternative.