Technology in terms you understand. Sign up for the Confident Computing newsletter for weekly solutions to make your life easier. Click here and get The Ask Leo! Guide to Staying Safe on the Internet — FREE Edition as my thank you for subscribing!

What Information Does a Laptop Leak on a Wireless Network?


What identifying signatures are given off by my laptop when I’m connected to a wireless network? I’m sure that my WiFi card, hard drive, Windows ID, and other identifying information is broadcast, but what is it? Would I guess that a traffic sniffer would show the make and model of my computer? Or does it go deeper than that?

Actually, it doesn’t go that deep at all. In general, it’s not as much information as you list… as long as you’re doing things right.

Become a Patron of Ask Leo! and go ad-free!

Doing it right

Let’s start with a secure connection to a wireless hotspot that requires a WPA or WPA2 encryption key. All of the data that gets transmitted between your laptop and the hotspot is encrypted, so sniffing, seeing, or understanding anything interesting in it is basically off the table.

The MAC address is actually visible. That’s a hardware serial number that’s used by your wireless network card. It’s actually how the wireless access point says that “this packet” is destined for “that machine.” It identifies “that machine” by the MAC address. In most cases, you might be able to determine the manufacturer and the model number of the wireless card from the MAC address. That’s just a side effect of how MAC addresses are assigned.

Knowing that, someone sniffing can figure a few things out. They might realize that that card only works in these PCs, or that the wireless interface is actually in a mobile phone, or those kinds of things. Certainly nothing that is specific to your particular computer.

And that’s about it. I really can’t think of anything else that would actually be exposed in a properly secured wireless connection.

That’s why a secure wireless connection is so important… because it’s secure.

Open hotspots

Someone's Peeking! Now, what about that open WiFi hotspot where there is no WPA or WPA2 key?

Most of what you list is actually not automatically sent out. I can’t see how or why information about your hard drive or your Windows ID would automatically be transmitted anywhere.

Now, it is important to note that any information that you cause to be transmitted over an open network could, of course,  be seen.

That could include what you described and probably more, depending exactly on what it is that you’re doing or how it is that you’re using that network connection. But by default, it’s still not very much.

On an open WiFi connection,  things like the machine name might be visible. If you have file sharing turned on in Windows, then the names of the shares that you make available could be visible. Again, if you don’t have the firewall turned on and no security on those shares, then it’s possible that the very contents of those shares could be visible.

But I have a hard time coming up with much more than that, especially if the Windows firewall has been turned on.

Posted: November 15, 2013 in: Privacy
Tagged: , , ,
« Previous post:
Next post: »

New Here?

Let me suggest my collection of best and most important articles to get you started.

Of course I strongly recommend you search the site -- there's a ton of information just waiting for you.

Finally, if you just can't find what you're looking for, ask me!

Confident Computing

Confident Computing is the weekly newsletter from Ask Leo!. Each week I give you tools, tips, tricks, answers, and solutions to help you navigate today’s complex world of technology and do so in a way that protects your privacy, your time, and your money, and even help you better connect with the people around you.

The Ask Leo! Guide to Staying Safe on the Internet – FREE Edition

Subscribe for FREE today and claim your copy of The Ask Leo! Guide to Staying Safe on the Internet – FREE Edition. Culled from the articles published on Ask Leo! this FREE downloadable PDF will help you identify the most important steps you can take to keep your computer, and yourself, safe as you navigate today’s digital landscape.

My Privacy Pledge

Leo Who?

I'm Leo Notenboom and I've been playing with computers since I took a required programming class in 1976. I spent over 18 years as a software engineer at Microsoft, and after "retiring" in 2001 I started Ask Leo! in 2003 as a place to help you find answers and become more confident using this amazing technology at our fingertips. More about Leo.

Leave a reply:

Before commenting please:

  • Read the article.
  • Comment on the article.
  • No personal information.
  • No spam.

Comments violating those rules will be removed. Comments that don't add value will be removed, including off-topic or content-free comments, or comments that look even a little bit like spam. All comments containing links and certain keywords will be moderated before publication.

I want comments to be valuable for everyone, including those who come later and take the time to read.