Network monitoring / scanning

Every day for about 5 hours, in the afternoon, my internet connection slows down. I am using a linksys wireless-G router to which I am connected via a cable.

I think someone is piggy-backing off my wireless signal and eating up my bandwidth.

If I were in Europe, it wouldn’t bother me all that much as there I have a 24000kb download and 7000kb upload connection.

However at the moment I am in the Caribbean and only have 256kb down and 64kb up.

I know there is a application that I can run that will allow me to see who is on my network and which will allow me to kick anyone “alien” off my home network. I just for the life of me remember what it is called.

Help please.

If you have WPA security enabled access point and couple that with MAC address access control, it seems unlikely that this could happen.

On Thu, 2009-12-10 at 05:26 +0000, silkmaze wrote:
> Every day for about 5 hours, in the afternoon, my internet connection
> slows down. I am using a linksys wireless-G router to which I am
> connected via a cable.
>
> I think someone is piggy-backing off my wireless signal and eating up
> my bandwidth.

The linksys has a firewall and logging… you should be able
to use that to find out for sure if somebody is “piggy-backing”.

>
> If I were in Europe, it wouldn’t bother me all that much as there I
> have a 24000kb download and 7000kb upload connection.

It would still bother me :slight_smile:

>
> However at the moment I am in the Caribbean and only have 256kb down
> and 64kb up.
>
> I know there is a application that I can run that will allow me to see
> who is on my network and which will allow me to kick anyone “alien” off
> my home network. I just for the life of me remember what it is called.

Well… if the person is getting an address via dhcp, you can
also enforce MAC filtering on the linksys to keep other off
of the device… but obviously, it depends on the sophistication
of the hacker.

On 12/10/2009 10:12 AM, cjcox wrote:
> On Thu, 2009-12-10 at 05:26 +0000, silkmaze wrote:
>> Every day for about 5 hours, in the afternoon, my internet connection
>> slows down. I am using a linksys wireless-G router to which I am
>> connected via a cable.
>>
>> I think someone is piggy-backing off my wireless signal and eating up
>> my bandwidth.

If you are connected via cable, turn wireless off. Then no one will be
able to piggyback.

If you still need wireless, then use WPA2 encryption with a passphrase
of 20-30 characters. No ordinary hacker will be able to crack that. A
good encryption scheme is much better than MAC filtering.

I would follow lwfingers advice. If you still want to scan your router use tools like iftop, tcp-dump or wireshark.

silkmaze <silkmaze@no-mx.forums.opensuse.org> writes:

> Every day for about 5 hours, in the afternoon, my internet connection
> slows down. I am using a linksys wireless-G router to which I am
> connected via a cable.
>
> I think someone is piggy-backing off my wireless signal and eating up
> my bandwidth.
>
> If I were in Europe, it wouldn’t bother me all that much as there I
> have a 24000kb download and 7000kb upload connection.
>
> However at the moment I am in the Caribbean and only have 256kb down
> and 64kb up.
>
> I know there is a application that I can run that will allow me to see
> who is on my network and which will allow me to kick anyone “alien” off
> my home network. I just for the life of me remember what it is called.
>
> Help please.

I assume you’ve also taken into account ‘the last mile’ bottleneck, which
affects all of us, at peak times.

As you stated you don’t have a fast Internet connection, you may notice
this more now than when you have a faster connection.

Assuming you are using WPA, I would be more inclined to assume it is the
ISP rather than the neighbours slowing your connection down.

Having said that, I would still log into the router and check exactly
who’s connected, if I were suspicious.


Regards,
Barry Nichols

Guys, thanks for all the suggestions and help.

I did have WPA installed, however the problems turned out to be more prosaic, my router was on its’ last legs, despite being only about 6 months old. Being on an island in the middle of no-where, warranties don’t really count for much. Its’ not like I can just run down to the shop where I got it from and get a replacement. As it happens, I called someone I know who was flying yesterday and he picked up a new one for me. I installed that, and bingo, I was up and running and there was no loss of speed.

I’ll be going off island between Xmas and new year and I’ll pick up a couple of spares, router, HDD’s, DVD burner, graphics card. Something I should have done months ago.

Again, thanks for all your help, guys.

Island life, ain’t it grand? (Here we’re lucky to have 75% uptime from the isp.)

OMG!!! 75% uptime. You truly live in Paradise. We pay through the nose for, “up-to” 65% uptime. And “up-to” 512kb down.

It is possible that the upgrade of router’s OS (which is likely Linux) will revive the router.

Seconded, try asking here:
RouterTechHome

Very helpful types, lots of handy utils and info etc etc.

In the final instance I couldn’t even get access to the router. I would type in the IP and wait, after a a while I would get an error message saying that the IP could not be reached.

If I can’t reach the router how do I update the software?

There should be a reset button at the back of the router, small pin size hole. Get a fine needle and press it in there. If you do it while router is off and switch the power on at the same time - most routers will do a Factory re-set. Sometimes this clear up problems :slight_smile: