Originally Published: Tuesday, 11 September 2001 Author: IRC Staff
Published to: interact_articles_irc_recap/IRC Recap Page: 2/2 - [Printable]

No Strings Attached: Recaps from LinuxWorld

LinuxWorld and a few more Live! presentations are over. We went through two setups of a wireless network using Linux at LinuxWorld this year. Now that it's all over, it's time to look back at the presentations and view some IRC logs from the events.

August 29 log  << Page 2 of 2  

00:32:13 we're live from the show floor
00:33:18 I'll be inputting what Dean says
00:33:19 Okay, I'll make the channel moderated - If anyone has questions during hte event, please /msg lcModerator
00:33:23 --- xeno42 sets mode +m #live
00:33:41 I know he's going to want to start off with definitions of wireless networking, and 802.11b
00:33:58 we've got a volunteer to work on the gateway
00:34:39 stats on the cards: Orinico 802.11b Silvers from Lucent
00:34:54 dean's talking about live! now; he just introduced gareth
00:34:55 Okay, so a wireless network consists of computers equiped with radio-frequency network cards instead of the normal wired-network cards.. 802.11b defines a standard for these cards to use
00:34:58 wave to the crowd, gareth :)
00:35:04 * xeno42 waves!
00:35:27 So the first thing we're going to do is set up the gateway
00:35:41 --> Inner^Cit (dante2600@vickesh01-1822.tbaytel.net) has joined #live
00:35:45 and a gateway is a central access point that all the computers on the network connect to
00:35:47 With the 802.11b standard, cards from different manufacturers conforming to the standard will interoperate with each other
00:36:17 --- xeno42 has changed the topic to: Current event is the 'No Strings Attached' event Live from Linuxworld in San Francisco - Learn how to setup a wireless (802.11b) network with Linux! /msg lcModerator with your questions
00:36:33 we're checking to see if the card works (if the computer sees it)
00:36:51 --> Diablo-D3 (diablo@iprs1-63-163-41-53.panax.com) has joined #live
00:36:54 by doing cat /var/lib/pcmcia or something similar (I didn't quite hear it)
00:37:06 there are a variety of ways you can install the wireless-tools package
00:37:18 apt-get install in Debian, rpm for Red Hat or Mandrake, or you can always compile from source
00:37:28 so we've installed that
00:37:33 and we're going to configure it using iwconfig
00:37:39 which reports just like ifconfig
00:37:51 it reports what wireless cards are in and what wireless extensions we have
00:37:57 so right now it's not reporting anything
00:38:04 so we're going to configure it
00:38:12 we need a definition for ESSID
00:38:33 We should note at this point that Dean, on stage, is already using a kernel with a few things compiled in - iptables, netfilter, ip masquerading (NAT) and is using the pcmcia-cs package rather than the pcmcia support compiled into the kernel
00:38:52 we're going to assign the ESSID "lclive" to this card
00:38:57 the ESSID is a text identifier that identifies which network our machines are talking to
00:39:16 by doing this command:
00:39:18 we could choose any piece of text, as long as all the machines that want to talk to the network are using the same identifier
00:39:32 iwconfig eth1 ESSID="lclive"
00:39:40 err
00:39:44 there are some more options there ;)
00:40:11 iwconfig eth1 ESSID="lclive" mode="Ad-Hoc"
00:41:06 eth1 is the name Linux has given to the wireless network card in teh gateway machine - eth0 is the name of the regular network card that's already in teh machine and will be used to connect to the Internet
00:41:13 right-o
00:41:25 so the command didn't work here; turns out the card wasn't in the whole way
00:41:27 *grin*
00:41:35 that always helps ;-)
00:41:40 now we're going to type iwconfig again
00:41:42 err
00:41:44 iwconfig eth1
00:41:55 so it should show us that the wireless extensions are there
00:42:34 the audience is helping us out here by pointing out that some machines require that you do the above command on different lines
00:42:43 like setting ESSID and mode seperately
00:43:12 because they're finicky
00:43:29 and when in doubt, you can always edit the file manually
00:43:41 which I believe is the /etc/pcmcia/wireless.opts file
00:43:46 (at least in Debian)
00:43:46 that's the one
00:44:43 well, the laptop seems to be downright finicky
00:44:49 it doesn't like anything we're doing
00:44:57 keebler steps in to save the day!
00:45:01 wow
00:45:14 to recap for our irc viewers, the goal here is to connect two laptops together over a wireless network and to make one of those laptops a 'gateway' to the Internet
00:45:16 it turns out we had to set Ad-Hoc mode first *before* setting the ESSID on this one
00:45:53 so now the wireless interface works on this machine
00:46:08 and we need to be able to pass packets through this machine to the other one when we get it set up
00:46:21 There are various 'modes' that wireless networks can operate in, 'Ad-hoc' is the simplest to setup and doesn't require any special equipment or software or organization
00:46:31 so we're going to set up iptables
00:46:39 if you're using 2.2.x, you can use ipchains
00:46:45 or is it the other way around?
00:46:48 anyway
00:46:59 yep, 2.2 is ipchains
00:47:00 Dean's written a little script that does all this
00:47:08 we're using ipchains since the gateway box is 2.2
00:47:09 which we'll try to get pasted into IRC
00:47:29 and if we can't do it here, we'll put it into the log later on when we post it on Linux.com
00:47:41 basically we're setting up masquerading here
00:47:48 and there are 109826513515 tutorials out there to do this
00:47:52 :)
00:48:12 Masquerading will let you share one internet connection between multiple computers
00:48:32 So now we have the gateway all set up
00:48:43 and we're going to set up the client; we have a new volunteer
00:48:53 since this is the client, we don't have to set up ipchains/tables
00:49:28 we should just be able to repeat our steps to configure wireless-tools and set the ESSID and mode the same
00:49:38 something just segfaulted or something; bad.
00:49:39 ...
00:49:52 ok, we're running the same iwconfig commands as above
00:49:53 iwconfig segfaults sometimes, but still works
00:50:05 iwconfig eth1 ESSID="lclive"
00:50:14 iwconfig eth1 mode="Ad-Hoc"
00:50:31 now we're setting up the network using ifconfig, just like a wired network
00:50:59 (if anyone has any questions as we go through this, please /msg lcModerator)
00:51:10 we're using 10.10.1.0 as the network, 10.10.1.1 as the gateway
00:51:21 it should also be noted that there are gui interfaces to iwconfig to make things easier (gnome_wireless, etc)
00:51:28 255.255.255.0 as the netmask
00:51:56 we went back to the gateway to setup the wireless network settings
00:52:02 and then set the same stuff on the client
00:52:12 what's the range on this stuff again?
00:52:15 30-100 m
00:52:16 ?
00:52:21 indoors, 30-100 metres
00:52:29 so we could walk around the booth with the client laptop
00:52:33 outdoors, 300 metres+ depending on conditions/equipment
00:52:36 hook up a webcam, anything
00:52:53 dean's talking about interference; these cards run in the 2.4 GHz range
00:52:58 which is the same as many cordless phones
00:53:04 so you have to be careful of things like that
00:53:18 we have a Q from the audience
00:53:56 oh, someone from the audience brought up the point that the client can actually stay in managed mode, doesn't need to be ad-hoc as long as the gateway is
00:54:41 someone else brought up the fact that your gateway can be pretty much anything that can run Linux; so anything 386+
00:55:07 Security is a big issue; there's some security built in, but there are ways to get around that
00:55:15 there are different things you can do to boost security
00:55:22 someone in the audience mentioned nocat.net, who has a portal system you can download and run on small access point boxes to track users
00:55:23 you can restrict your network to certain MAC addresses
00:55:39 always need to run encryption, like SSH and SCP over your network
00:55:45 never transmit passwords in the clear ;)
00:55:49 There has been a lot of media coverage recently about how WEP (Wired Equivalent Privacy) isn't particularly secure
00:56:01 Does anyone here know if there is support for USB and wireless?
00:56:02 --> chaser (mountwc@216.124.227.45) has joined #live
00:56:30 someone here thinks it'll be in in around a month
00:57:11 these Orinoco cards do have a port where you can plug in an external antenna
00:57:17 to boost the range
00:57:30 and I've heard that there's a hack using a Pringles can as a directional antenna ;)
00:57:40 yes, that's also on nocat.net
00:58:32 <-- muks has quit (Signed off)
00:58:43 --> muks (muks@217.154.34.18) has joined #live
00:58:53 we're showing off the pringles can hack on nocats on the big screen right now
00:58:58 the audience loves it ;)
00:59:05 and if you can do that, and microwave ovens run at the same frequency, there must be some hack to produce an 800 watt amplifier if you take the oven door off
00:59:06 <-- muks has quit (Signed off)
00:59:10 --> muks (muks@217.154.34.18) has joined #live
00:59:10 "This stuff is really really cool" says someone in the audience
01:00:11 someone here's saying that the pringles can hack is not very different (in quality) from the commercial directional antennas
01:00:42 and of course much much cheaper ;)
01:01:10 Cisco (or someone) makes base stations
01:01:16 so you don't even have to have two computers
01:01:21 it's like the Apple Airport base
01:01:33 you can buy many different makes of Access Point
01:01:48 which can be used to setup larger, more structured wireless networks
01:02:20 we've got a disassembled AirPort station here
01:02:26 and it has one of the Orinoco cards in it
01:02:58 someone here just asked how much power you need to fry birds in the air
01:03:07 and someone else answered "about a watt and a half"
01:03:15 the people here are weird
01:03:38 :)
01:03:44 sounds like someone let the geeks in
01:03:58 someone asked if concrete was an issue
01:04:00 like concrete walls
01:04:13 the answer seems to be that it won't go through the concrete itself
01:04:25 but if there are any gaps or anything, it'll go through those
01:05:00 <-- Diablo-D3 (diablo@iprs1-63-163-41-53.panax.com) has left #live
01:05:23 --> Diablo-D3 (diablo@iprs1-63-163-41-53.panax.com) has joined #live
01:06:35 ok, we're all finished up here
01:06:50 if anyone here has anything to add, go for it
01:06:51 the network works?
01:07:01 yep, we've been surfing for about 15 minutes ;)
01:07:08 great ;-)
01:07:18 deltab Diablo-D3 droidix 01:07:25 Diablo-D3 asks ' couldnt you theoretically set up a series of relay stations to relay a single tens of miles using 3 or 4 relay points along the way?'
01:07:25 Diablo-D3 asks ' couldnt you theoretically set up a series of relay stations to relay a single tens of miles using 3 or 4 relay points along the way?'
01:08:13 can anyone in the channel answer that?
01:08:24 if you can get line of sight, and buy the right antennas (or pringles tubes, I guess) then you can do it in one hop
01:08:54 ok, I'm going to log off here; thanks everyone for coming out!
01:08:56 :)
01:10:53 hey xeno, okay, how far will los communications work?
01:11:06 people have managed like 25 miles
01:11:29 but you need some serious preparation to make that work
01:12:16 hmm
01:12:41 think about it, if you can even do 25 miles, think about several hops of that
01:13:24 you'd have problems with reliability, actually *getting* LOS, etc
01:13:49 hmm... still
01:13:53 <-- keebler has quit (ircII EPIC4-1.0.1 -- Are we there yet?)
01:15:21 there should be a way to do simple communications easly like that
01:15:57 heh.. i don't think you'll find that 25 mile transmission is simple by anyone's definition ;-)
01:16:13 what about even 5?
01:16:30 get about 100 people in a small area....
01:16:40 and set it up somehow so local hubs speak to each other
01:16:40 have a look on the 'net.. there are a number of people using 802.11 technology to do that
01:16:44 and share bandwith...
01:17:07 businesses are around doing exactly that
01:17:21 hmm
01:17:30 buisnesses are inherently evil too
01:17:36 I want something thats free
01:17:50 <-- flip- has quit (If at first you don't succeed, destroy all evidence that you tried.)
01:18:04 just buy the hardware and poof
01:19:40 i mean, imagine what that could do
01:19:52 copper and fiber telecommunications could be worthless
01:20:29 i mean, you would only need them for Top Priority communications
01:20:34 --> Blu3 (david@Huntington-Beach.Blue-Labs.org) has joined #live
01:20:53 and the whole net structure could be mostly redone, having only the required nodes comunicating with each other
01:20:55 wireless is no substitute for a real wired connection
01:21:18 http://www.guerrilla.net/
01:21:32 i ment for under 11mbps stuff
01:21:35 not major servers
01:21:43 but major servers could have wireless apart of their network too
01:21:59 so you could skip the landlines, and just walk up to it and download stuff from it
01:22:04 well if you don't mind having your connection disappear every now and again, that's fine
01:22:10 all depends what you need
01:22:37 connections disappear every now and then anyhow
01:22:46 dialup, equipment failures
01:22:48 it all happens
01:22:55 not with the same frequency
01:22:57 <-- lukin has quit (lukin has no reason)
01:23:04 not when a police car drives by your house heh
01:23:32 I suggest you set yourself up a wireless network at home and get used to it's properties for a bit
01:23:40 it's wonderful, but you'll understand what I mean
01:24:23 wireless adds severe latency
01:24:44 --- xeno42 has changed the topic to: Last event was the 'No Strings Attached' event Live from Linuxworld in San Francisco - Logs will be up on Linux.com during the next week - See http://linux.com/ for details of other live events
01:24:49 10Mb/s latency is about 1 - 2ms for an ne2k card, not too bad
01:25:12 however wireless is usually about 10-15ms for roughly 2Mb/s
01:25:14 yeah well, i dont have the $ to do that
01:25:18 nor is it worth the money
01:25:22 i only have two boxen.
01:28:31 <-- Diablo-D3 has quit (Do coders dream of sheep()?)





August 29 log  << Page 2 of 2