Good Free or Cheap Network Monitoring Tools

I'm using a dlink wireless router to share the internet connection between myself, my roomate, and someone in the next apartment over. I want to make sure they don't have any spyware or applications sucking up all my bandwidth. Are there any good free/cheap tools to accomplish this?

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check out, I've been testing ethereal out on a non-production network and I am liking the features I see.  Especially since its free.  Sadly (in one sense) its giving the pay software a real good run for the money.

Microsoft Defender blew my hat off in its capabilities, Succesfully removed all the stuff the common spyware tools where not able too.

Good luck
stopher2475Author Commented:
I'm not looking for spyware utilities. I'm looking for some kind of app that can look at my network and tell me if one of the hosts is using an unusual amount of traffic or doing something suspicious.
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>> I want to make sure they don't have any spyware or applications sucking up all my bandwidth

Make sure they dont have any.

If you are actually trying to "monitor" the actuall traffic buy "managable" equipment like a managable firewall (cunsumers language : Cisco Types), router, switches. Then hook up syslog servers to that equipment and generate events based on the entries made. Or buy a switch that can create vlans next configure a "forward all" port, and hook a sniffer up that port. And read the thousants of entries...

My professional oppinion, make them aware of the dangers. Teach them to monitor their systems. Or just install a "spyware" tools on their machines and setup "smart" filter rules. But next to that, all "examples" mentioned above are company like sollutions... and a bit overdone for home networks i take.

i can hand you tools to monitor host alive, service alive on remote machines, (domains may use QoS policies) Monitor Disk IO, Memory consumption, CPU Usage.. But actuall trafic "to" the internet is usually monitored at the router.

Cheap home sollution would be to setup a linux machine acting as router with two interfaces, next use that linux machine as network router by hooking your witch in interface 1, and router/modem in interface 2 and monitor it from linux. Else i leave you little chance...

Regards Chris
try PRTG traffic monitor. YOu can monitor 3 things for free via SNMP if your router supports it. Buy the full edition to monitor more things.

I think this is wot ur after
ethereal is great, but it usually gives you too much detail... and it's not real-time...

you could try using ntop ( on a computer, but ntop will see traffic only reaching this computer... you could try using a hub to connect this computer to your router, or a switch with port mirroring...

ntop is great, and free if you use linux... if you use windows, you can try compiling it, or you can pay the fee... if you can, do it on linux (easier, cheaper)...
thanks to lrmoore on another question (

here's ntop free on windows:
Hi marce_lito,

You may want to check out ethereal.  I don't think you are fully aware of ethereal's features.  I'm trying to figure out why you don't think it outputs information in realtime or why you are no aware of its filtering features.   L 8 R

Actually, I love ethereal and I use it almost every day... but not for monitoring... It's much better suited to analyze specific problems rather than to do normal monitoring... ntop will give you who's talkingto who using which protocol easily, without having to set up filters or anything...

And I really don't know how to use ethereal in real time... I really don't...  I just caputre packets and then analyze them
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