Contact US

Log In

Come Join Us!

Are you a
Computer / IT professional?
Join Tek-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Tek-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Packet analyzer question

Packet analyzer question

Packet analyzer question

I have a question that I just cant quite get my head around.  I need to put a Packet sniffer on the network.  But I cant seem to get it in a place that is getting data from all computers.  My setup is like this

Router --> Firewall -->  Switch  -->  Desktops
                    --> Switch   -->  Desktops

 If I plug into the switch I get broadcast data from all computers but unicast data goes by without being detected.  I know that is the point of the switch is to keep unwanted unicast packets out of the picture.  But here is the question.  Do I have to put a hub between the firewall and switch and hang a workstation off the hub as well to capture all the data coming out of the switch?  

Just thought I would bounce that off of you?

RE: Packet analyzer question

To catch unicast packets you would need the two switches the desktops connect to be able to mirror all the ports to one port to sniff in.  I am not sure off the top of my head if switches do that.  I think you can though.

If you put a hub between the desktop switch and the firewall you will never see packets that do not leave the switch.

If you are only concerned with data that goes from the desktops off your network you can mirror (span port in cisco terms) the uplink port on each switch and sniff.


........99.9% User Error........
Ubuntu -- African for I can't install Gentoo

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Tek-Tips Forums free from inappropriate posts.
The Tek-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Tek-Tips forums is a member-only feature.

Click Here to join Tek-Tips and talk with other members! Already a Member? Login

Close Box

Join Tek-Tips® Today!

Join your peers on the Internet's largest technical computer professional community.
It's easy to join and it's free.

Here's Why Members Love Tek-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close