AUTHOR: Dr. Edgar Alwers DATE: 2006-12-10 LICENSE: GNU Free Documentation License Version 1.2 SYNOPSIS: Wireless Communication from the sources PREREQUISITES: BLFS 6.x with kernel 2.6.18 DESCRIPTION: This is a Hint explaining how to prepare a PC for wireless communication with the Internet and how to put it into operation. I solved this problem with the help of hints and advices given by many persons, and working through lots of papers, many of them not beeing actual anymore at this time. The object I had to deal with is an 'Acer' TravelMate 291LCi with Intel Centrino Mobile Technology, equiped with an Intel PRO/Wireless 2200BG(IEEE 802.11b/g) chip. The Laptop communicates with an 54 Mbps Wireless Netgear ADSL Firewall Router DG834G as access point However, there are good chances, that this hint may also be applied to other PC's with other drivers. If you cannot obtain a native Linux driver for your wireless NIC, you may want to try 'ndiswrapper', a package that will allow to load a Windows driver under Linux. The kernel compiled is version 2.6.18. This kernel includes already an 'old' driver ipw2200 and a iee802 subsystem, which should not be enabled, as they are beeing provided separate. Additional instructions are given, how to operate a PC in a wireless field under a DHCP Server ( Dynamic Host Configuration Protocol ) providing IP's to the clients. This is the probably situation which will be found in most public locations, like airports, hotels etc. HINT: KERNEL Download: Kernel v. 2.6.18 http://www.kernel.org Configuring the kernel: enable Networking-> Networking support-> Networking options-> Packet socket TCP/IP networking device drivers-> Network device support-> Wireless LAN (non-harmradio)-> Wireless LAN drivers & Wireless Extensions cryptographic optionsI-> ARC4 cipher algorithm (Modul) Make sure, that the following capabilities are not enabled: networking-> Generic IEE 802.11 Networking Stack device drivers-> Network device support-> Wireless LAN ( non-hamradio ) -> Intel PRO/Wireless 2200BG and 2915ABG network compile and install the kernel according to the instructions of the book 'Linux From Scratch' HOTPLUG-2004_09_23 Scripts that react upon hotplug events generated by the kernel Download: hotplug-2004_09_23.tar.bz2 http://www.kernel.org/pub/linux/utils/kernel/hotplug Install hotplug issuing a 'make install' in the untared directory. IEE80211-1.2.15 Kernel subsystem dealing with communications security Download ieee80211-1.1.15.tgz http://ieee80211.sourceforge.net Untar the file, change to the ieee80211-1.1.15 directory and enter make, make install. Includes headerfiles in /lib/modules/2.6.18/net INTEL'S PRO/WIRELESS DRIVER AND FIRMWARE Download the file ipw2200_linux_1_2_0.tgz http://ipw2200.sourceforge.net Unter the file. Two new tar files will be included in the new created 'intel_ipw2200_120' directory: ipw2200-1.2.0.tgz, the PRO/Wireless driver, and ipw2200-fw-3.0.tgz, the firmware. Untar the firmware file in the directory /lib/firmware. Four files ipw-2200-xxx.fw will be found there after untaring Untar the PRO/Wireless driver file, change to the ipw2200-1.2.0 directory and enter make, make install. ( as su ) The driver requires the firmware image as well as the ieee80211 module installed. sysfs should be already mounted See also the INSTALL file for more instructions THE WIRELESS TOOLS Set of tools that allows to manipulate Wireless Extensions Download the wireless tools: wireless_tools.28.tar.gz http://pcmcia-cs.sourceforge.net/ftp/contrib/ Untar the file, change to the wireless_tools.28 directory and enter make, make install Seven tools will be installed in /usr/local/sbin: iwconfig, iwlist, ifrename,iwevent,iwgetid, iwpriv and iwspy Make a link from KDE_Prefix/bin to /usr/local/sbin: ln -s /usr/local/sbin/iwconfig KDE_Prefix/bin/iwconfig THE DHCPCD CLIENT SOFTWARE Software to connect a computer to a network which uses DHCP to assign network addresses.There are two alternatives: dhcp, which includes also the server software, and dhcpcd, an implementation of the DHCP client specified in RFC2131. I prefered dhcpcd, wich seems to be more simple. Download dhcpcd-2.0.8.tar.bz2 http://prdownload.berlios.de/dhcpcd/ Untar, change to the dhcpcd-2.0.8 directory and enter ./configure --prefix="" --mandir=/usr/share/man make and, as superuser, make install, and chmod -v 754 /etc/dhcpc/dhcpcd.exe. The reason for the prefix "" in the configuration command is explained in the blfs-book, version svn-20061028, chapter 14. Install the network service script /etc/sysconfig/network-devices/services/dhcpcd and create /etc/sysconfig/network-devices/ifconfig.eth1/dhcpcd configuration file as indicated in the same place BOOTING THE PC If everything went right, the PC boots and loads firmware and wireless-driver. The corresponding booting messages will look like ........ ieee80211_crypt: registered algorithm 'NULL' ieee80211: 802.11 data/management/control stack, 1.1.6 ieee80211: Copyright (C) 2004-2005 Intel Corporation ipw2200: Intel(R) PRO/Wireless 2200/2915 Network Driver, 1.0.8 ipw2200: Copyright(c) 2003-2005 Intel Corporation ACPI: PCI Interrupt Link [LNKG] enabled at IRQ 10 ACPI: PCI Interrupt 0000:01:02.0[A] -> Link [LNKG] -> GSI 10 (level, low) -> IRQ 10 ipw2200: Detected Intel PRO/Wireless 2200BG Network Connection Detected geography ZZM (11 802.11bg channels, 0 802.11a channels) ......... MONITORING PROGRAMS There are many prrograms that allows the monitoring of wireless communications. I installed two of them: 'Wireshark' ( former ethereal ) and 'KWiFiManager'. 'wireshark' is a powerfull network protocol analyser ( packet sniffer ). Download 'wireshark-0.99.4.tar.gz' from http://www.wireshark.org/download/src Untar the file and run ./configure, make and make install. 'kwifimanager' is a KDE frontend program used to configure and monitor wireless LAN cards. 'kwifimanager' is part of 'kdenetwork'. Download kdenetwork_3.4.1.tar.bz2 and follow the instructions given e.g. In BLFS - Version 6.1, chapter 29. Wireless tools should be installed before building this packet. CONFIGURING THE ROUTER - SAFETY CONSIDERATIONS during the installation of the wireless system, the safety options of the router are deactivated. Now, it is time to activate them. Access the settings menu of the router through a browser, entering something like http://192.168.0.1. I activated WEP ( Wired Equivalent Privacy ) with 64 bit encryption. You may consider a 125 bit encryption Enter a password in the encryption field, and the router will generate four keys, each one consisting of 10 characters, combining numbers 1 to 9 and letters A-F, like:EC670531BE. The first of this four keys is the one beeing normally used. Furthermore, the MAC-addresses ( Media Access Control ) of the laptop's and PC's wich are allowed to access the router shoud be entered in the access list 'trusted wireless stations'. You may get the MAC addresses from the list of connected devices in the settings menu of the router or with the help of a network exploration tool like 'nmap' ( Network Mapper ), in the last case e.g. entering 'nmap -sP 192.168.0.1/22' However, even a 125 bit encryption does not give a real security today. According to a note contributed by Bryan Kadzban, real security can only be obtained with WPA or WPA2 encryption. You may want to consider this, if you have confidential data to transmit. CONFIGURING THE PC FOR WIRELESS COMMUNICATIONS immediately after the safety options of the router are activated, the PC will not more be able to see the access point: the PC also needs to be configured. Entering the command 'iwconfig eth1 key xxxxxxxxxx' enables the communication, but not permanently. For a permanent configuration, write a shell-script e.g.'connect' in /etc/rc.d/init.d: $!/bin/sh /usr/local/sbin/iwconfig eth1 key xxxxxxxxxx and make this script executable: chmod ug+x connect. Make a symbolic link in /etc/rc.d/rc3.d that points to this script: ln -s /etc/rc.d/init.d/connect S19connect. The link should start with something like S19, as the script should be run before the S20network script is executed. For an unencrypted system, likely to be found on public places, the command in the script should not contain a key: /usr/local/sbin/iwconfig eth1 Create a directory 'ifconfig.eth1' in '/etc/sysconfig/network-devices', and cd to this directory. For operation withouth DHCP create a ipv4 file: ONBOOT=yes SERVICE=ipv4-static IP=192.168.1.3 // the address of your box GATEWAY=192.168.1.9 // the address of your router PREFIX=24 BROADCAST=192.168.1.255 NETMASK=255.255.255.0 and change GATEWAY_IF in /etc/sysconfig/network to eth1. For operation with DHCP create instead ipv4 a file dhcpcd: ONBOOT="no" SERVICE="dhcpcd" DHCP_START="eth1 -t 20" DHCP_STOP="-k " # Set PRINTIP="yes" to have the script print # the DHCP assigned IP address PRINTIP="yes" # Set PRINTALL="yes" to print the DHCP assigned values for # IP, SM, DG, and 1st NS. This requires PRINTIP="yes". PRINTALL="no" USING THE WIRELESS CONNECTION After booting, lsmod shows Module Size Used by ipw2200 170244 0 ieee80211 45356 1 ipw2200 ieee80211_crypt 4512 1 ieee80211_crypt_wep, ieee80211 The command 'iwconfig eth1' entered in a console delivers eth1 IEEE 802.11g ESSID:"Mannheim" Mode:Managed Frequency:2.462 GHz Access Point: 00:0A:B5:CF:64:28 Bit Rate=48 Mb/s Tx-Power=20 dBm Sensitivity=8/0 Retry limit:7 RTS thr:off Fragment thr:off Encryption key:57E4-DB3A-B1 Security mode:open Power Management:off Link Quality=95/100 Signal level=-29 dBm Noise level=-86 dBm Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:0 Invalid misc:0 Missed beacon:0 As the ONBOOT parameter was set to 'yes', the connection to the access point is already activ. The internet browser should be configured with direct access to the internet. Opening the browser should establish immediately a connection. USING THE WIRELESS CONNECTION UNDER A DHCP SERVER I experienced some problems starting the dhcpcd daemon during the boot process. So I decided to set the ONBOOT parameter in the file /etc/sysconfig/network-devices/ifconfig.eth1/dhcpcd to 'no', as indicated above, and to start as 'su' a little script 'eth1_connect' : #!/bin/bash /sbin/dhcpcd eth1 # end After starting the daemon dhcpcd, the connection to the access point is activ. AKNOWLEDGEMENTS: I have tryed to compile articles, informations, hints and answers to questions I put in the BLFS-mailing list to this hint. Many thanks to all those who contributed: Gabe Yoder, Andrew Benton, Alexander E. Patrakov, Jim Gifford, David Fix, Rainer Peter Feller, Chris Staub, Randy McMurchy, Jeremy Monnet, Stefan Krah, Bryan Kadzban. LINKS AND LITERATURE: Intel PRO/Wireless driver http://ipw2200.sourceforge.net Linux Wireless Networking http://www.linuxhomenetworking.com/linux-hn/wmp11-linux.html Wireless LAN Resources for Linux http://www.hpl.hp.com/personal/jean_Tourrilhes/Linux/Tools.html Wiresharkt http://www.wireshark.org/ The devices, the drivers... Jean Tourrilhes http://www.hpl.hp.com/personal/jean_Tourrilhes/Linux/Linux.Wireless.drivers.802. 1.11ag.html#CentrinoAG Sane network interface management with Hotplug. Jean Tourrilhes http://www.hpl.hp.com/personal/jean_Tourrilhes/Linux/HOTPLUG.txt ndiswraper http://ndiswrapper.sourceforge.net/mediawiki/index.php/Installation CHANGELOG: [2006-03-26] Remarks concerning safety considerations Additional notes concerning DHCP-Server operation Chapter "The DHCPCD Client Software" Configuring the PC for operation under DHCP Subsystem IEE80211-1.1.6 changed to IEE80211-1.1.12 Intel PRO/WIRELESS driver ipw2200-1.0.8 changed to ipw2200-1.0.10 Using the wireless connection under a DHCP server [2006-12-10] Kernel version 2.6.18 Kernel configuration changed Hotplug instructions changed UDEV is now part of the system ieee80211 version changed to 1.2.15 New versions of Intel's PRO/Wireless driver and firmware Wireless tools version 28 dhcpcd version 2.0.8 new message booting the PC 'Kismet' skipped, 'wireshark' introduced Links and literature changed