How to check computers connected?

Hello All! I set up a wireless router at home, and it works very well. I didn't use WEP becuase my laptop's Wireless NIC doesn't support it. Now I want to see all the computers currently using my wireless router, is there a way to do that? Thanks!

SIncerely, Ben

Reply to
Benny Van
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Are you certain that your wireless NIC doesn't support WEP? What is the Make and Model and version number of your wireless NIC?

Reply to
Doug Jamal

Use this freebie. Easy to use.

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Very good little app.

Cheers

Rob

Reply to
me here

Thanks - this is a cool utility, but there is a minor problem - it does not detect my Linux boxes connected to the network. Has anyone else noticed this?

Stuart

Reply to
Stuart Miller

Out of curiosity can you "ping" them from the machine that is running "Lanspy". One of the family tried the program and them uninstalled it, reason given was that it hadn't picked up one of the laptops that was using wireless. This laptop runs ZA Pro and does not respond to being pinged or allow sharing of any kind, before I could double check the program and been removed and the laptop had disappeared out of the door.

Reply to
Kev

The two linux machines are configured in normal security, without local firewall. They both run samba, for workgroup based shares, as I run both xp and win98 on other machines here. Both are readable & writeable for shares, one runs as my print server, and both respond properly to ping. It took a while, bit I finally have it so that everybody can see everybode else.

Everything here lives behind a firewall/router.

My wireless laptop just died, so I have to wait until my son comes by with his laptop to test the wireless detection.

Stuart

Reply to
Stuart Miller

Had a little play this morning. Lanspy with it's default options. Laptop1 using wireless with ZA, no sharing and no response to ICMP Echo. Laptop2 using wireless with Windows firewall , no sharing and no response to ICMP Echo.

Lanspy does not see either laptop.

If I allow sharing or ICMP Echo on either Laptop then Lanspy will see them.

If I change Lanspy's options to not check "Ping" then it will detect the MAC addresses of both laptops even if they do not allow sharing or do not respond to ping. However if the laptops are locked down it takes forever to do a complete scan of all the checks that Lanspy can carry out and it is best just to check for MAC addresses if you are checking to see if anyone is piggybacking onto you network. Shame it doesn't seem to have an option for continuous scanning.

Reply to
Kev

Kev hath wroth:

Where are you plugged in to do your sniffing? Locating a sniffer is not a trivial exercise. In the typical home system, there is no single place where you can see all the traffic.

If you're computah running Lanspy, Ethereal, etc is plugged into an ethernet switch or into the switch on the back of the typical router, then it will not see any traffic other than broadcasts and it's own traffic. The purpose of the switch is to not pollute the rest of the network with un-necessary traffic. If you replaced the switch with an ethernet hub, which is essentially a repeater where all traffic going into any port appears on the other ports, you will be able to see the other traffic.

For sniffing internet traffic (bear with me for this diversion) you need to add a hub (not a switch). The general arrangement is:

DSL or cable router ====== PC modem ========== ethernet ======= and ethernet ====== Linux hub (not switch to other ====== MAC a switch) computers | | | \\============= monitor computer running the sniffer

With this arrangement, the monitor computer will see all internet traffic, including intruders and attacks from the internet.

There are also products specfically available for doing sniffing.

You can also build your own (as I've done because I'm cheap).

If you specifically are trying to minitor just the wireless traffic, it cannot be done in a "wireless router". That's because there's no way to "tap" the traffic between the router section and the wireless access point sections of the "wireless router". If you just plug into one of the ethernet jacks on the back of the wireless router, you will see broadcasts from various wireless attackers, but not see their traffic.

The only place where you will see MOST of a wireless attackers traffic is on the WAN side of the broadband link. If the wireless traffic is mostly on the LAN side of the router, you will only see perhaps DNS lookups from a wireless attacker. Another way is to sniff the wireless traffic directly over the air, which gets only the wireless traffic, and not those from the wired ethernet computers.

Reply to
Jeff Liebermann

The PC running Lanspy was wired into a combo modem/router, a speedtouch variant known as a BT Home Hub( regrettably my Linksys has just died on me). As there had been several mentions of Lanspy recently one of the family decided to try to see if it could see all of the computers on the network, he wasn't interested in actual traffic, and he found he could not see one laptop. Rather than try to find out why he ditched the program and went off with the Laptop. Out of curiosity I decided to run some checks this morning to see why the Laptop hadn't been seen.

Reply to
Kev

Ok. It may be called a "hub" but it's really a combination modem, router, wireless?, and ethernet switch. It's the switch part that's the problem. YOu can't see traffic on one port, that's going to/from any of the other ports (except broadcasts). Try it by watching the lights. Copy a big file between two of the ports and see if anything lights up on a 3rd or 4th port in which you're plugged into. It won't flash indicating that you cannot use the 3rd or 4th ports to monitor the traffic on the 1st or 2nd ports. Incidentally, the wireless access point section is just a 5th port on the ethernet switch and acts the same as the other ports.

The Linksys whatever wouldn't have helped. The only way you're going to monitor traffic with such an arrangement is by using seperate boxes for modem, router, wireless, and ethernet switch. Even so, there's no single point that will sniff ALL the traffic. Welcome to the wonderful world of network monitoring. This is one reason why router/switch based traffic monitoring protocols like SNMP, RMON, NetFlow, etc are popular.

If the laptop is running Windoze XP, it might be that the firewall is configured to reject just about everything. As I vaguely recall, ICMP ping is blocked in the default configuration. Control Panel -> Windoze Firewall -> Exceptions -> Advanced

Reply to
Jeff Liebermann

The "Hub" doesn't have such niceties, it came as a freebie when we upgraded to "up to 8Mb" broadband.

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No, but it worked well for the last 3 years with only minor hiccups and lately had been used to allow visitors to access the web without having to use my main wireless network.

Thanks for all the info.,it has been very informative. The easiest way for Lanspy to "see" the locked down laptops was to disable the ping check, in options, and only look for MAC addresses.

Reply to
Kev

I enabled Ping, DNS name, MAC and Server, and disabled everything else. It found the linux machines and reported properly When I get more time I'll try to find out which test gets confused by the linux servers.

Stuart

Reply to
Stuart Miller

The tinyurl didn't show anything. I got a blank page. However, I found the BT Hub elsewhere. Only one ethernet jack. One would think that plugging a cheap ethernet hub (not a switch) into this port and you will see all the traffic. Nope. There's still a 3 port switch inside the box. One port to the router, one to the wireless, and one to the external ethernet connector. Same problem as before. You don't see any of the traffic not specifically designed to or from the monitoring PC. In order for this to be useful for external monitoring, you would have to divorce the router from the wireless access point sections (which can't be done), or simply disable the wireless section, and use an external wireless access point.

Thanks. That's what I try to be.

Yep. That's the passive sniff mode, which will pickup broadcasts. You should see those on any port since packets (such as broadcasts) that have no specific destination MAC address, go to ALL the ports on a switch.

Reply to
Jeff Liebermann

Not noticed that before, it seems that if I try to do a tinyurl for any of the specification pages on the BT Shop website it produces a blank page.

Was it this one, being pedantic, 2 ethernet Skt's

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Reply to
Kev

Kev hath wroth:

That's usually what happens with a web site that uses a "content management system" or "web applications framework". The various pages are assembled on the fly, are often dependent on what was previously viewed, and often have URL's that only work for a specific session. The URL's are sometimes impossible to bookmark.

Chuckle. I used Google images. I just wanted a general clue as to what it looked like. See:

for a variety of BT Home Hubs. I assumed it was one of the 2Wire devices, some of which have only one ethernet jack. I guess not.

Reply to
Jeff Liebermann

there a way to do that?

On the user interface for my DD-WRT router there is a "Wireless Status" screen, it lists "Wireless Clients" - MAC address, signal, etc. Which is probably what you want to know, check if there are any strangers getting on your LAN, right?

There is also a DHCP lease table in DD-WRT' - it shows the MAC address and Host Name of addresses given out by the router recently. Besides showing who's on the ethernet LAN it can also indicate if somebody connected wirelessly recently but may be off now. Anybody who recently got a DHCP lease that is -

Of course, that only works if you have a DD-WRT kind of router.

If you still had your Linksys....

Reply to
seaweedsteve

On the user interface for my DD-WRT router there is a "Wireless Status" screen, it lists "Wireless Clients" - MAC address, signal, etc. Which is probably what you want to know, check if there are any strangers getting on your LAN, right?

There is also a DHCP client table in DD-WRT' - it shows the MAC address and Host Name of addresses given out by the router recently. Besides showing who's on the ethernet LAN it can also indicate if somebody connected wirelessly recently but may be off now. Anybody who recently got a DHCP lease that is -

Of course, this only works if you have a DD-WRT router.

Reply to
seaweedsteve

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