programmatically know who's connected to a router

is there a way to programmatically know who's connected to my router
?
either wireless or by cable
either via DHCP or with static address ?
there should be, because on my router (netgear) there is a page that
shows "connected devices" ...
i've googled without success
Thank you for any hint

On Feb 3, 1:11*am, michi...@email.it wrote:
> is there a way to programmatically know who's connected to my router
> ?
> either wireless or by cable
> either via DHCP or with static address ?
> there should be, because on my router (netgear) there is a page that
> shows "connected devices" ...
> i've googled without success
> Thank you for any hint

Simply precisely define what you mean by "connected", and check for
that. Presumably, your DHCP server has a database of assigned
addresses somewhere. It's not clear what it would mean for something
to be "connected" to your router with a static address. So I don't
think it makes any sense to check for that.

Linux does keep track of pseudo-connections that can be created by any
packet passing through the computer and kept around for some time.
This may be the information you actually want -- history of recent
packets passing through your router. Punch 'linux connection tracking'
into your favorite search engine.

DS

On 2009-02-03, (E-Mail Removed) <(E-Mail Removed)> wrote:
> is there a way to programmatically know who's connected to my router
> ?
> either wireless or by cable
> either via DHCP or with static address ?
> there should be, because on my router (netgear) there is a page that
> shows "connected devices" ...
> i've googled without success

Connected to the router means very little.
I'm going to asssume you mean "Who's in my router's network?".

Look into nmap.

Start with nmap 192.168.0.* (assuming that would be your network).

--
Elevators smell different to midgets

(E-Mail Removed) wrote:
> is there a way to programmatically know who's connected to my router
> ?
> ...
> there should be, because on my router (netgear) there is a page that
> shows "connected devices" ...

All that means is there is a way to get that information from a
program running on the netgear itself. It does not imply there is
some API you could use on another system to reach-out and ask the
netgear - short of a program mimicing what you are doing when browsing
the netgear's web interface.

rick jones
--
firebug n, the idiot who tosses a lit cigarette out his car window
these opinions are mine, all mine; HP might not want them anyway...
feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...

First of all: sincere thanks to all who spent their time answering my
question, i really appreciate.
Simplyfing (cutting down?) my question:
i'm trying to discover if someone is connecting wireless to my home
network that is unprotected.
I've tried to implement WPA, but on the windows PCs it causes
performance degradation and random disconnects, and on linux (ubuntu)
i didn't succeed at all to get connected, so i gave up :-(
Now i think the best solution (workaround) is nmap, simply scanning
the addresses that are in my router (netgear DG834Gv3) dhcp range.

On Tue, 03 Feb 2009 23:45:18 -0800, michiedo wrote:

> First of all: sincere thanks to all who spent their time answering my
> question, i really appreciate.
> Simplyfing (cutting down?) my question: i'm trying to discover if
> someone is connecting wireless to my home network that is unprotected.
> I've tried to implement WPA, but on the windows PCs it causes
> performance degradation and random disconnects, and on linux (ubuntu) i
> didn't succeed at all to get connected, so i gave up :-( Now i think the
> best solution (workaround) is nmap, simply scanning the addresses that
> are in my router (netgear DG834Gv3) dhcp range.

No, the "best solution" is to figure out why you are unable to use WPA.
It isn't difficult, and it should not degrade performance to any
noticeable degree. Spend your time solving the problem, not searching
for a bandaid to put on it.


--
"Ubuntu" -- an African word, meaning "Slackware is too hard for me".
The Usenet Improvement Project: http://improve-usenet.org
Ahhhhhhh!: http://brandybuck.site40.net/pics/relieve.jpg

Hello,

Andrew Gideon a écrit :
>
> More importantly: nmap might not catch well-firewalled devices.

One might have better luck doing an ARP scan for each possible IP
address in the subnet, e.g. using arping in a loop. Even a node dropping
any unexpected incoming IP packet should reply to an ARP query in order
to be able to receive IP packets. However in order to better hide itself
a node may reply only to ARP queries coming from nodes (local router or
host) frow which it expects IP traffic. In this case, the best you can
do is watch ARP queries from these nodes which need to learn the MAC
address of the hidden host in order to deliver return traffic to it.
This may be done with tools such as arpwatch. Of course this won't work
if the hidden node only listens to traffic passively.