Who Else is Using My Router, How to Check

[nujinini]

Hello,

I tried to google around for some answers and tried to search into some threads in LF but can't seem to hit it.

May I please ask what to execute in the Terminal in order to checkon who else (ip) is/are using my router at a certain time.

I am using Ubuntu by the way.

Thank you!

regards,

nujinini

[atreyu]

Is your Ubuntu server also your router, or do you have a stand-alone router? Is it wireless? Typically, routers have an embedded webserver running which provides a simple GUI method for configuring / reviewing the configuration and system logs might be there for you to look at.

[sgosnell]

Log on to your router using your browser. You should have set up an admin username and password when you installed it, but if you didn't, it may still use the default. That varies by manufacturer, so Google your router brand and you can find the defaults. It's a very bad idea to use those, since anyone with internet access can easily get into it and change our settings. If you've changed the username/password and forgot it, you can always reset the router to factory defaults. When you get logged in as admin, there should be a page on the router which shows all the DHCP clients. You should be able to filter those able to log on by MAC address or other parameters. You should always enable WPA2 security on your router, using a different password than the admin password. Letting anyone use it, and using the default admin settings is begging for trouble.

[nujinini]

Thank you atreyu and sgosnell,

I am using a wireless router at home and have already set it up with an admin password too.

Actually, what I want to know is to identify the different ip address of the others using our network. My machine for example is 192.168.1.5. If my sons are using the same network with their own machines. How will I be able to check their respective IP ads. Sorry if my question is confusing. And thanks again for your replies.

[atreyu]

Well, I'd still recommend going to the wireless router itself and looking for logs on it for information regarding DHCP and/or connection attempts.

If you're lucky, the router will support rsyslog - which basically means you configure it with an ip address (that of your linux machine) and it will forward the syslog messages to your Linux machine's rsyslog server. You'll have to configure this on the linux server, too, but it is a simple two-line edit of one file.

Now, if you just want to do a network scan, which will report any devices found with an ip address on that network, this is simple, too. Nmap is a good way to do this, e.g.:

nmap -n -sP 192.168.1.0/24

This will just do a ping scan (versus also looking for open ports, which would take longer) of the network given. If run as root, it will also display the associated MAC addresses - handy for identifying a specific computer...

[jayd512]

When logging into your router, you should have an option labeled Local Network or DHCP Client Table.
On a Linksys, this shows the Client Host Name, MAC address of the machine that is connected wirelessly and the IP addy that they have obtained.

If you see a computer that shouldn't be there, you can sever the connection. After that, put their MAC address into the MAC filtering section to deny access.

[sgosnell]

It depends on the router, because each manufacturer has its own setup. Somewhere in the router settings there should be a DHCP client list, or something like that, which should show the IP addresses for every connected machine, computers, printers, and all. If you can tell us the router make and model, we can Google that and find the information for you, or you could do it yourself. Without knowing more about your router, I can't tell you much more about where to look.

[nujinini]

Thank you for all the suggestions.

My router is an Asus.

I don't know what model though.

[atreyu]

It should have the model # on the underside or something.

Go here and see if you can spot it, then tell us.

[nujinini]

It an Asus WL520gu

Thanks!