| View previous topic :: View next topic |
| Author |
Message |
jeanluca
Apprentice
Joined: 08 Jan 2005
Posts: 179
|
 Posted: Sat Jan 08, 2005 5:18 pm Post subject: Scanning for wireless networks |
 |
|
Hi All
At the moment I'm configuring my wlan. But normally I surf the web via the (not) encrypted wireless internet from my neighbours. All that is easy when using windows XP......
So does linux has tools to scan for wireless networks and check on signal strength?
And how does windows XP deals with ESSID ?
I never specified something like that there ?
Thanks in advance !
Luca |
|
| Back to top |
|
 |
aspenhydrowave
n00b
Joined: 08 Dec 2004
Posts: 41
|
| Posted: Sat Jan 08, 2005 5:54 pm Post subject: Re: Scanning for wireless networks |
|
|
| jeanluca wrote: | Hi All
At the moment I'm configuring my wlan. But normally I surf the web via the (not) encrypted wireless internet from my neighbours. All that is easy when using windows XP......
So does linux has tools to scan for wireless networks and check on signal strength?
And how does windows XP deals with ESSID ?
I never specified something like that there ?
Thanks in advance !
Luca |
If you want real 'scanning' you can check out a program called airsnort, although your wireless card firmware must support monitor mode. The legality of this is questionable.
If you want to just see what networks are available (as opposed to listening for packets on them) just set essid_eth0="any" (or eth1 or whatever your wireless device is).
If you want to check signal strength you can do iwconfig (Link Quality=43/92 Signal level=-72 dBm Noise level=-115 dBm) or cat /proc/net/wireless (similar information in a different format)
In XP, essid is what the computer is talking about when it says "connect to [network name]." When it gives you a list of available networks to connect to, that is actually a list of essid's. |
|
| Back to top |
|
|
aspenhydrowave
n00b
Joined: 08 Dec 2004
Posts: 41
|
| Posted: Sat Jan 08, 2005 5:56 pm Post subject: Re: Scanning for wireless networks |
|
|
| Sorry, essid_eth0="any" should be done in /etc/conf.d/wireless |
|
| Back to top |
|
|
jeanluca
Apprentice
Joined: 08 Jan 2005
Posts: 179
|
| Posted: Sat Jan 08, 2005 11:49 pm Post subject: |
|
|
Thanks a lot, finally I understand essid 
But suppose I've configured my wireless device correclty, eth1=dhcp, set essid to "any" etc,
and I turn it on. Which wireless netowrk does it go for. Mine, or the one from the neighbour ? How does it choose?
Luca |
|
| Back to top |
|
|
aspenhydrowave
n00b
Joined: 08 Dec 2004
Posts: 41
|
| Posted: Sun Jan 09, 2005 4:11 pm Post subject: |
|
|
| jeanluca wrote: | Thanks a lot, finally I understand essid
But suppose I've configured my wireless device correclty, eth1=dhcp, set essid to "any" etc,
and I turn it on. Which wireless netowrk does it go for. Mine, or the one from the neighbour ? How does it choose?
Luca |
That is an excellent question that I really have no answer for. There are a couple of wireless networks floating around here, and it seems to connect to the unprotected ones kinda randomly (once it's up it stays on one unless I force it over though). I would recommend, if you want to make sure that it connects to your network, just set eth1_essid="[your essid]" which you should be able to set in your wireless router admin page somewhere. Note that essid's are case-sensitive.
Also, if you're just configuring a network now, an off-topic tip: in /etc/conf.d/net set dhcpcd_eth1="-N" if you are using ntp, otherwise dhcp will overwrite your /etc/ntp.conf. Took me months to figure that one out...
Update: I just checked and that's the old format. the new one is dhcp_eth1="nontp". |
|
| Back to top |
|
|
andyknownasabu
Apprentice
Joined: 06 Feb 2003
Posts: 281
Location: Zurich, Switzerland
|
| Posted: Sun Jan 09, 2005 5:17 pm Post subject: Re: Scanning for wireless networks |
|
|
| jeanluca wrote: | Hi All
At the moment I'm configuring my wlan. But normally I surf the web via the (not) encrypted wireless internet from my neighbours. All that is easy when using windows XP......
So does linux has tools to scan for wireless networks and check on signal strength?
And how does windows XP deals with ESSID ?
I never specified something like that there ?
Thanks in advance !
Luca |
I would recommend the tool kismet (net-wireless/kismet) to scan for wireless networks:
http://www.kismetwireless.net/ |
|
| Back to top |
|
|
jeanluca
Apprentice
Joined: 08 Jan 2005
Posts: 179
|
| Posted: Sun Jan 09, 2005 5:21 pm Post subject: |
|
|
So far, I think iwlist does the job for me, it shows all the wireless networks, and is very simple!!!
Luca |
|
| Back to top |
|
|
UberLord
Retired Dev
Joined: 18 Sep 2003
Posts: 6837
Location: Blighty
|
| Posted: Mon Jan 10, 2005 9:42 am Post subject: Re: Scanning for wireless networks |
|
|
| aspenhydrowave wrote: | | Sorry, essid_eth0="any" should be done in /etc/conf.d/wireless |
Sorry, but essid_eth0 should only be set when the card does not support scanning.
Setting it to "any" tells the card to pick an access point - which makes things like the preferred_aps list, blacklisted, etc etc redunandant. |
|
| Back to top |
|
|
aspenhydrowave
n00b
Joined: 08 Dec 2004
Posts: 41
|
| Posted: Wed Jan 12, 2005 9:04 am Post subject: Re: Scanning for wireless networks |
|
|
| UberLord wrote: | | aspenhydrowave wrote: | | Sorry, essid_eth0="any" should be done in /etc/conf.d/wireless |
Sorry, but essid_eth0 should only be set when the card does not support scanning.
Setting it to "any" tells the card to pick an access point - which makes things like the preferred_aps list, blacklisted, etc etc redunandant. |
Very interesting - this is how I do it and it works for me - but what and how should be set so that it scans for available networks on networking startup and 'just works'? |
|
| Back to top |
|
|
UberLord
Retired Dev
Joined: 18 Sep 2003
Posts: 6837
Location: Blighty
|
| Posted: Wed Jan 12, 2005 10:53 am Post subject: Re: Scanning for wireless networks |
|
|
| aspenhydrowave wrote: |
Very interesting - this is how I do it and it works for me - but what and how should be set so that it scans for available networks on networking startup and 'just works'? |
Nothing - it scans by default
Here's what I use myself
| Code: |
key_Uber_NET="s:thisisakey enc open"
key_DevNET="s:deventkey enc open"
preferred_aps=( "Uber NET" "DevNET" ) |
With default settings only we scan for unencrypted AP's and connect to them |
|
| Back to top |
|
|
luca
Guru
Joined: 11 Feb 2004
Posts: 374
|
| Posted: Wed Jan 12, 2005 12:28 pm Post subject: |
|
|
I learn new thing everyday, thanks!!
Can someone tell me where I can find detailed information about wireless network configuration??
Luca |
|
| Back to top |
|
|
syg00
l33t
Joined: 23 Aug 2004
Posts: 907
Location: Brisbane, AUS
|
| Posted: Wed Jan 12, 2005 12:45 pm Post subject: Re: Scanning for wireless networks |
|
|
| jeanluca wrote: | | At the moment I'm configuring my wlan. But normally I surf the web via the (not) encrypted wireless internet from my neighbours. All that is easy when using windows XP...... |
You must have friendly (stupid) neighbours.
I'd *pay* you if you could drop in on my wireless network.
On top of WEP and assigned MAC addressess, I have a German Shepherd.
You need to get past him to get in range of the router.
Good luck
 |
|
| Back to top |
|
|
menschmeier
l33t
Joined: 15 Dec 2004
Posts: 727
|
| Posted: Fri Feb 11, 2005 9:59 am Post subject: |
|
|
Hello,
the availability of scanning is depending on the hardware, isn't? How can I find out if this works for me? I am using a centrino laptop.
Thanks
_________________
Please notice the back of this message. |
|
| Back to top |
|
|
uncleringo
Tux's lil' helper
Joined: 21 Jul 2004
Posts: 146
|
| Posted: Fri Feb 11, 2005 10:18 am Post subject: |
|
|
menschmeier,
Not sure if it's a good way of checking but I just found out that I can't scan by trying:
# iwlist scanning
wlan0 Interface doesn't support scanning : Function not implemented
But this is possibly only because i'm using linux-wlan-ng |
|
| Back to top |
|
|
menschmeier
l33t
Joined: 15 Dec 2004
Posts: 727
|
| Posted: Fri Feb 11, 2005 10:24 am Post subject: |
|
|
Hi,
now it works because I am in rage of an open wlan ...
iwlist eth1 scanning
eth1 Scan completed :
Cell 01 - Address: xxxxxxxxx
ESSID:"xxxx"
Protocol:IEEE 802.11b
Mode:Ad-Hoc
Channel:11
Encryption key:off
Bit Rate:11 Mb/s
Extra: Rates (Mb/s): 1 2 5.5 11
Extra: Signal: -59 dBm
Extra: Last beacon: 10ms ago
Ok, thats easy. I think its an open access point in my company .... 
Thanks a lot.
_________________
Please notice the back of this message. |
|
| Back to top |
|
|
|
Networking & Security
