How can you tell when people are on your network?

Self explanatory. I'm not suspecting of anything or anyone, I'm just simply curious as to how you could tell if someone else was using your network.

 

If you are using a router, you can check the log of your router. You'll have to login to your router, but there should be an option either called Router log, or something about devices connected to your router. I know that Netgear has a router log and keeps track of any MAC address that connect to it, so I'm pretty sure that DLink and Linksys have this same feature.

SG

 

Ok, I found this and enabled it. But, wouldn't it have incoming connections from the internet and so forth? Or how will I tell its another person/computer connecting? Also, how do you tell if they are actually using your connection or not?

 

It depends on the router. Some show port scanning, attacks, outgoing activity, connections to blocked addresses, etc. According to Netgear's site, the purpose of logging is to record information about traffic coming into your LAN.

I can't double check on this but I think it shows the MAC address on each entry. Each wireless card has its own MAC address, so if you know your MAC addresses that connect, it should be fairly easy to spot the connections that aren't yours.

Some firewalls (I know PC-cillin does this) have the ability where it detects any connection to your network. You install PC-cillin on each computer, and it is able to detect any computer that connects to your network. I haven't ever used this feature, but I think it does give you a message on any computer not authorized to connect to your laptop.

 

Angry IP Scanner is a nice utility:
http://www.angryziber.com/ipscan/

 

I have a Linksys WRT54g router and all it shows is the source IP and the destination port.

 

Hi jparker,

You can check your network workgroups in windows anytime. You can also check DHCP leased IP addresses on router (it shows you the IP and MACs). This is probably the best place to check. Windows networking is slow updating and logs can be difficult to read.

Cheers,

 

Download a program named netscan

 

You can always do the old school way, go to command prompt and type Net View. It will show all the PCs on you subnet.

 

How do I go about checking this? I am new to all of this so please bare with my ignorance.

 

Hi jparker,

Every router should have DHCP settings. You can access the router from Internet browser by typing its address. 192.168.1.1 or 192.168.2.1 should cover the most of the cases. Login. Find something like DHCP table. There should be some table with IP addresses (the addresses that your router has assigned to each client by DHCP). Usually in the same table can be the MAC address (unique hardware based address of the each network adapter connected) and sometimes the name of the comp (host name). Similar to the picture below.

Cheers,

 

Read the Linksys user guide for your router, it's on the product page at linksys.com. Below is a pic of what you're looking for in the router setting.

 

If your router has DHCP off, or if some of the computers are using static IPs, it may not list them there.

 

Hi dr_st,

How the router knows to whom to send the packet then? Just occured to me. It could be that if you disable DHCP - the whole page becomes disabled and you can't see the table. I didn't try it though!

Cheers,
Ivan

 

Maybe this is a dumb question, but reading the above made me think of it. Could someone from the outside somehow log into my router and change settings on me?

 

I believe I am capable of answering this one. Someone correct me if I'm wrong. But if they were connected to your network then they could type that in and it would come up, but they would still need to know your password. So I'm assuming that as long as they don't know your password you're good.

 

By the way, thank you. I read the guide for my router but I suppose I missed that part. Thanks again.

 

Like you said - it's just that some routers don't display this info when DHCP is off. Mine doesn't. Come to think of it, it's not very good implementation. Surely the router knows who is connected at any given point. It's a shame that sometimes it won't tell you.

 

Hi dr_st,
I agree. I wonder why is it so. They obviously believe that router must have its DHCP enabled - or otherwise you don't need that info? Strange.

jparker - I'm glad that everything is solved now.

Cheers,


Ivan

 

Indeed. From the pic posted by lazybum it appears that the Linksys behaves just like my Edimax - only displays DHCP clients (unless there's another table somewhere). The only router so far where I've seen something that resembles a full network log is Trendnet. But it's general user interface is so horrible, that it's barely useful at all.