Is there a utility out there to detect if someone is using your wireless connection?

[Trizzay]

Hey guys. I'm looking for a freeware tool that can be used to alert you if someone is trying to leech off of your wireless connection. I know I can secure my wireless connection, but rather than do that for now I'd like to have some fun with my neighbors and see if they are actually using my wireless. I'd love to find something that sends out an audio alert or something along those lines if it detects that someone else jumps on my connection. Thanks!

 

[C1]

"Ethereal" will do it.

 

[postmortemIA]

Just look at your router's list of DHCP leased IP addresses.

 

[nova2]

if you use wireshark you can capture all packets going to and from the wireless device or router. so unless they have an encrypted tunnel going, you will be able to see the text of all packets, so that means all the HTML and text if they're web surfing, or all instant message text if say they were using MSN messenger.

if you have the right software, you can reconstruct all the packets to make things somewhat easier.

but if they're using an encrypted tunnel for all their traffic, then you're 99% in the dark and clueless.

 

[Jeff7181]

Originally posted by: postmortemIA
Just look at your router's list of DHCP leased IP addresses.

This assumes the thief is using DHCP. The IP ranges used by routers are so common, it wouldn't be difficult for a thief to find out the default gateway and DNS servers and just set all that along with a static IP address, still use your wireless, but not show up as a DHCP client.

Best bet is to lock down the router so a key must be entered to connect. You could even go as far as setting MAC filtering for wireless devices. That's enough to deter 99% of people who steal wireless.

 

[papaschtroumpf]

Most routers will show the MAC address of associated devices.
Ethereal and Wireshark are great solutions, but only if you know what you're looking at.

 

[earthman]

Why aren't you using a WEP key or WAP?

 

[jdport]

I know for me, when I configured WEP/WAP it gave me nothing but trouble. My computers had trouble connecting to my router, and they would constantly drop the connection. It was such a pain in the ass I just dropped the security. So it isn't secure... i don't keep personal info on my computer anyway so, it isn't that big of a deal. Haven't noticed anybody ever leaching off of me so far. If there was an easier way to configure it and have it just work, I'd do it... but it hasn't been worth the hassle to me.

 

[LuDaCriS66]

It's not just about what you have ON the computers. It's about what you do over the internet connection as well. Without encryption, a lot of what you do over the network goes through the air in plain text. All someone has to do is sit there, turn on a passive sniffer, and get all that data. It is always in your best interest to use some sort of encryption.

 

[earthman]

You might want to rethink that. If someone uses your connection to do something illegal, for example, it's you that they are going to come after.

 

[poisonthewell]

Originally posted by: Trizzay
Hey guys. I'm looking for a freeware tool that can be used to alert you if someone is trying to leech off of your wireless connection. I know I can secure my wireless connection, but rather than do that for now I'd like to have some fun with my neighbors and see if they are actually using my wireless. I'd love to find something that sends out an audio alert or something along those lines if it detects that someone else jumps on my connection. Thanks!

As others have mentioned, lock your connection down. When you do, you'll have an answer as to whether your neighbors are using your connection.

 

[Luden]

I've never tried this program, but it sounds like what you might be looking for: AirSnare

From the FAQ:

Q: What does this program do?

A: AirSnare monitors network traffic for unfriendly MAC addresses and alerts you when a MAC address is found that isn't on the friendly list. AirSnare also monitor DHCP requests from clients.

 

[imaheadcase]

My wireless router, the D-Link DIR-655 actually shows the name of the computer connecting. My bother uses his wifi on phone to connect to my router sometimes and actually shows HTC Touch in router log. Even computer names from wireless laptops that i allow to connect.

 

[Markbnj]

You really should lock down (not to pile on here... but really). If the client computers are losing the connection with WEP enabled, then what is probably happening is that you have them set to connect to any available network, and when they temporarily lose the connection with your router they go hunting for another one. There's a checkbox for this setting ("Automatically connect to available wireless networks"). I don't use wireless here in my office so I can't check to see exactly where it is, but maybe someone else here can help with that. Once this checkbox is cleared you should get a stable connection to the network you select (i.e., yours).