Changing Channels

With my Linksys 54G router, I noticed another network (D-Link
router) while sitting on my new deck. So I enabled WEP. Then
I changed from channel 6 to channel 1. Now the other network
no longer shows up. As long as he stays on channel 6, does this
mean he's not detecting my network? I live in the woods, and I
don't suspect hackers.

Scott

No - changing channels does not prevent detection.

Check out http://www.netstumbler.com for free software that will easily
allow you to detect networks.

Check out
http://www.whitehats.ca/main/members...cess_point.pdf
for a good primer on how to close your network. This was for 802.11b will
apply to 802.11G as well.



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"Scott" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> With my Linksys 54G router, I noticed another network (D-Link
> router) while sitting on my new deck. So I enabled WEP. Then
> I changed from channel 6 to channel 1. Now the other network
> no longer shows up. As long as he stays on channel 6, does this
> mean he's not detecting my network? I live in the woods, and I
> don't suspect hackers.
>
> Scott
>

On Sat, 28 Aug 2004 23:28:04 -0600, Scott <(E-Mail Removed)> wrote:

>With my Linksys 54G router, I noticed another network (D-Link
>router) while sitting on my new deck. So I enabled WEP. Then
>I changed from channel 6 to channel 1. Now the other network
>no longer shows up. As long as he stays on channel 6, does this
>mean he's not detecting my network? I live in the woods, and I
>don't suspect hackers.

It's not clear is you saw your neighbors system from the access point
or from your laptop.

The way it works is that you set the channel on the access point.
That stays on whatever channel you set it to. In infrastructure mode,
the client radio in your laptop scans *ALL* the channels looking for
suitable access points. If you do a "site survey" or "scan for
available access points", your client radio is checking every channel.
Therefore, you should still see your neighbors system from the client
radios.

However, I vaguely recall that the WRT54G router has a similar "site
survey" feature that lists access points. However, since the access
point channel is fixed, it would only list those it hears on the same
channel number upon which it's set. Again, I'm not sure of this as I
don't have a WRT54G in front of me, and refuse to read the docs on
weekends (for sanity preservation).

There's another exception. If you're using the Ad-Hoc mode, all the
radios are client radios. It would be a bad idea to have them scan
all channels looking for each other. So, in Ad-Hoc, the channel
number of the client radio is fixed and does not scan. Running a
"site survey" on an ad-hoc system only lists radios that are on its
channel.


--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 AE6KS 831-336-2558

Jeff Liebermann wrote:
> On Sat, 28 Aug 2004 23:28:04 -0600, Scott <(E-Mail Removed)> wrote:
>
>
>>With my Linksys 54G router, I noticed another network (D-Link
>>router) while sitting on my new deck. So I enabled WEP. Then
>>I changed from channel 6 to channel 1. Now the other network
>>no longer shows up. As long as he stays on channel 6, does this
>>mean he's not detecting my network? I live in the woods, and I
>>don't suspect hackers.
>
>
> There's another exception. If you're using the Ad-Hoc mode, all the
> radios are client radios. It would be a bad idea to have them scan
> all channels looking for each other. So, in Ad-Hoc, the channel
> number of the client radio is fixed and does not scan. Running a
> "site survey" on an ad-hoc system only lists radios that are on its
> channel.
>
>

Not my experience.
I have a pc with wireless and a laptop with wireless
and changed channels several times to avoid same channel usage.

I was often in ad hoc mode and it keeps scanning
(in netstumbler anyway)

But could there be another reason?
May be the AP is not on all the time?

If the other signal is not an AP but a pc-peer then the
signal is only on when they have switched on the computer.

regards
hans

On Wed, 08 Sep 2004 22:50:08 +0200, hans <(E-Mail Removed)>
wrote:

>Jeff Liebermann wrote:

>> There's another exception. If you're using the Ad-Hoc mode, all the
>> radios are client radios. It would be a bad idea to have them scan
>> all channels looking for each other. So, in Ad-Hoc, the channel
>> number of the client radio is fixed and does not scan. Running a
>> "site survey" on an ad-hoc system only lists radios that are on its
>> channel.

>Not my experience.

I beg to differ.

>I have a pc with wireless and a laptop with wireless
>and changed channels several times to avoid same channel usage.

You can change channels in ad-hoc mode all you want. However, ad-hoc
mode does NOT scan for empty channels or compatible SSID's. You set
it for a specific channel and leave it there.

Note that the channel is specified in the ad-hoc setup in the
following instructions:
http://www.zyxel.com/support/support.../app/Adhoc.htm
http://www.hardavenue.com/reviews/adhocguide.shtml

>I was often in ad hoc mode and it keeps scanning
>(in netstumbler anyway)

Netstumbler is doing the scanning. It scans all the channels looking
for access points. In ad-hoc mode, there are no access points.
Netstumbler is very good about not trampling infrastructure or ad-hoc
connections and can be run simultaneously with either an ad-hoc or
infrastructure clients.

>But could there be another reason?
>May be the AP is not on all the time?
>If the other signal is not an AP but a pc-peer then the
>signal is only on when they have switched on the computer.

I'm sorry. I don't understand any of the above. Repeating again:
1. An access point is set to a specific channel.
2. Client radios scan all channels looking for access points.
3. All ad-hoc radios are client radios and are set to a fixed
channel. They do NOT scan channels but do scan for an IBSS network to
join.
4. Netstumbler is a client application and does not know anything
about ad-hoc or infrastructure modes. It scans channels looking for
infrastructure access points.
5. Netstumbler will detect ad-hoc clients, but seems to belch
multiple BSSID's with some (not all) ad-hoc clients.


--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831.336.2558 voice http://www.LearnByDestroying.com
# (E-Mail Removed)
# 831.421.6491 digital_pager (E-Mail Removed) AE6KS

Jeff Liebermann wrote:

> 4. Netstumbler is a client application and does not know anything
> about ad-hoc or infrastructure modes. It scans channels looking for
> infrastructure access points.

if you say so.

in one of its columns it says "ad hoc" or "AP"

seems to me it knows about it.