How can I find out which of my local computers are online?

Oak · Apprentice Joined: 25 Jan 2005 Posts: 239 Location: Sweden

This might sound like a stupid question, but I will ask it anyway.
I have a local network at home with one server/gateway, one desktop and two laptops. All of them are running Gentoo except one laptop, (which by the way is my girlfriends computer) that is running WinXP.
All computers shares my internet connection and are connected to the gateway/server.
Is there any way to find out which of the computers are currently connected to the local network (they are allways connected, except when they are not on), except to ping them? Netstat only shows external connections, and that is not what I want

Regards / Daniel
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GCC-4.3.3-r1 - march=core2, gentoo-sources-2.6.30-r2 SMP x86_64 @ Core2Duo 2.4GHz, 4GB RAM

mrBob · n00b Joined: 03 Feb 2006 Posts: 65

Is your gateway a hardware device or a PC built for that purpose? If it's external hardware you picked up at a store, don't they usually come with admin utilities that let you monitor traffic, usually accessible through a web interface if you have the admin uid/passwd combo? I ask cos mine is like that.

EDIT: Browse through the net-analyzer directory in Portage on packages.gentoo.org or gentoo-portage.com ... Everything available through Portage is listed there.

think4urs11 · Posted: Wed Feb 15, 2006 6:15 am Post subject:

In one way or annother you need to have these machines send out some kind of network packet to be *sure* it is online.

ideas for that:
- create a script on gateway to ping regulary all of them (or use nmap -sP, nbtscan -v, arping, ... for that)
- lower your dhcp lease time to e.g. 10 minutes(so the clients stay in your dhcp servers arp table while powered on)
- if your switch is managable check its port status via snmp

HTH
T.
_________________
Nothing is secure / Security is always a trade-off with usability / Do not assume anything / Trust no-one, nothing / Paranoia is your friend / Think for yourself

Oak · Apprentice Joined: 25 Jan 2005 Posts: 239 Location: Sweden

Ok, thanks for the replies. I will try out the different suggestions.

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GCC-4.3.3-r1 - march=core2, gentoo-sources-2.6.30-r2 SMP x86_64 @ Core2Duo 2.4GHz, 4GB RAM