calt129
December 18th, 2005, 12:05 AM
Hi there,
Back then under Ubuntu 5.04, and now under 5.10, I was pretty disappointed with the unreliably working Wlan profiles. It was partly due to the ever-changing interface names (which can be solved with /etc/iftab :) and the lack of settings possibilities in network-admin (which can be launched via Gnome's Wlan applet). Furthermore network-admin was really slow everytime I wanted to change profiles quickly. So I've taken the low-level path und stuck with /etc/network/interfaces, which I presume is used by these various tools anyway.
My primary interface is eth1 (Wlan) and I'm using eth0 (cable) very rarely but its configuration is very similar. There are 3 profiles for home (1 with static IP with WPA, 1 with DHCP with WPA and 1 with DHCP with WEP) and 2 profiles for work (1 with static IP with WEP and 1 with DHCP with WEP).
So, here's a sample interfaces file, an accompanying script to detect the current environment based on MAC-addresses of accesspoints, a sample wpa_supplicant.conf file and a small script to bring the interfaces down before suspending/hibernating the computer (they're upped automatically on resume) so that if you change the location during this suspension, your laptop gets automatically a new IP as soon as you power it on again.
I'll assume that you know how to run commands (such as in a terminal) and edit files (with vi, gedit, etc.)
Installation:
Check if you have the packages wireless-tools & resolvconf. You should already have wireless-tools and resolvconf is needed if you want to set dns-suffices & nameservers. You can check this either via synaptic or running:
apt-cache showpkg resolvconf.
Review the MAC-addresses and other settings in the profiles file. The MACs can be found by calling
iwlist eth1 scanning under "Cell xx- Address:..." line
Only then copy the profiles file to /etc/network/profiles (make a backup of the old file first!!!)
Copy the script to /usr/local/bin/scan-wireless-mac-address.sh (or wherever you want to but don't forget to change the path for in the profiles file)
Review and copy the WPA-configfile it to /etc/wpa_supplicant.conf if you're using WPA.
[This may change] Copy the interface-down script to /etc/acpi/suspend.d/48-networking-down.sh (or whatever name you see fit)
I've included some optional commands such as pre-up, post-down, etc. I'll explain those shortly:
Normally if you want to connect to a WPA-protected AP (accesspoint) you should start the WPA_supplicant first, even just to connect to the AP (correct me if I'm wrong).
After you connect to some AP and got your IP, you can also copy a network-specific hosts file to /etc/hosts, which is simply a list of statically defined IP-numbers to avoid DNS lookups. This step could be done prior to connection, too, but it sounds better this way.
Whenever you bring down an interface, it has no sense anymore that wpa_supplicant runs in the background, so it's safe to kill it in a post-down line.
The profiles file:
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
# The loopback network interface
auto lo
iface lo inet loopback
# This is a list of hotpluggable network interfaces.
# They will be activated automatically by the hotplug subsystem.
#mapping hotplug
# script grep
# map eth1
# The primary network interface
auto eth1
mapping eth1
script /usr/local/bin/scan-wireless-mac-address.sh
map eth1 11:22:33:44:55:66 homedhcp
map eth1 11:22:33:44:55:66 home
map eth1 11:22:33:44:55:66 homealt
map eth1 22:33:44:55:66:77 workdhcp
map eth1 22:33:44:55:66:77 work
iface homedhcp inet dhcp
pre-up wpa_supplicant -B -i eth1 -c /etc/wpa_supplicant.conf -D ipw -q
post-up cp /etc/hosts.home /etc/hosts
post-down killall wpa_supplicant
#post-up ifconfig eth1 mtu 1300
iface home inet static
pre-up wpa_supplicant -B -i eth1 -c /etc/wpa_supplicant.conf -D ipw -q
post-up cp /etc/hosts.home /etc/hosts
post-down killall wpa_supplicant
network 192.168.100.0
address 192.168.100.186
netmask 255.255.255.0
gateway 192.168.100.1
dns-nameservers 11.22.33.44 55.66.77.88
dns-search my.domain
mtu 1300
iface homealt inet static
post-up cp /etc/hosts.home /etc/hosts
wireless-mode managed
wireless-essid alternate-wlan
wireless-key s:0123456789 open
network 192.168.100.0
address 192.168.100.186
netmask 255.255.255.0
gateway 192.168.100.1
dns-nameservers 11.22.33.44 55.66.77.88
dns-search my.domain
mtu 1300
iface workdhcp inet dhcp
#post-up ifconfig eth1 mtu 1300
wireless-mode managed
wireless-essid office-wlan
wireless-key-1 s:1234567890123 open
wireless-key 012345678990ABCDEF01234567 open
mtu 1300
iface work inet static
post-up cp /etc/hosts.work /etc/hosts
wireless-mode managed
wireless-essid office-wlan
wireless-key-1 s:1234567890123 open
network 10.11.11.0
address 10.11.11.169
netmask 255.255.255.0
gateway 10.11.11.1
wireless-key 012345678990ABCDEF01234567 open
#dns-search myworkdomain.com
#dns-nameservers 10.11.11.3
mtu 1300
iface eth0 inet dhcp
mtu 1300
# activating the following line increases bootup time!
# alternatively, one can decrease the timeout value in /etc/dhcp3/dhclient.conf
# auto eth0
The script to detect accesspoints, based on their MACs (no change needed):
#!/bin/sh
# this script finds out if an Access-Point with the given MAC address is reachable
# prints the profile (last parameter) out
# returns 0 if found, 1 if not
# should be called from /etc/network/interfaces like this:
# map eth1 11:22:33:44:55:66 homewlan
if [ `id -u` != 0 ]; then
echo "You have to run this script as root"
exit 1
fi
if [ "$1" = "" ] ; then
echo "You have to pass an interface name, e.g. eth1"
exit 1
fi
BINIWLIST="/sbin/iwlist"
if [ ! -x $BINIWLIST ]; then
echo "$BINIWLIST does not exist or is not executable!"
exit 1
fi
IF="$1"
which=""
while read IFACE MAC PROFILE; do
if [ "$which" ]; then continue; fi
echo -n "Checking if access-point $MAC is reachable... " >&2
if $BINIWLIST $IFACE scanning | grep "Cell" | grep $MAC > /dev/null 2>&1; then
echo "OK. Using profile $PROFILE" >&2
which="$PROFILE"
else
echo "" >&2
fi
done
if [ "$which" ]; then echo $which; exit 0; fi
exit 1
The script to bring the interfaces down (no changes needed):
#!/bin/bash
if [ -e /etc/network/interfaces ]; then
# bring down all interfaces
ifdown -a
fi
Sample WPA config file (change the SSID & key, more info under https://wiki.ubuntu.com/WPAHowto):
# Minimal /etc/wpa_supplicant.conf to associate with open
# access points. Please see
# /usr/share/doc/wpasupplicant/wpa_supplicant.conf.gz for more complete
# configuration parameters.
ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=0
eapol_version=1
ap_scan=1
fast_reauth=1
### Associate with any open access point
### Scans/ESSID changes can be done with wpa_cli
network={
ssid="cu"
scan_ssid=1
proto=WPA
key_mgmt=WPA-PSK
psk=00112233445566778899aabbccddeeff00112233445566 778899aabbccddeeff
}
I hope this helps someone. All suggestions and corrections are welcome.
EDIT: I've found this post from another Ubuntu user. Pretty much the same technique (using iwlist & interfaces file), just a bit different. Link: http://lists.ubuntu.com/archives/ubuntu-users/2005-April/028964.html
Peace and out
Back then under Ubuntu 5.04, and now under 5.10, I was pretty disappointed with the unreliably working Wlan profiles. It was partly due to the ever-changing interface names (which can be solved with /etc/iftab :) and the lack of settings possibilities in network-admin (which can be launched via Gnome's Wlan applet). Furthermore network-admin was really slow everytime I wanted to change profiles quickly. So I've taken the low-level path und stuck with /etc/network/interfaces, which I presume is used by these various tools anyway.
My primary interface is eth1 (Wlan) and I'm using eth0 (cable) very rarely but its configuration is very similar. There are 3 profiles for home (1 with static IP with WPA, 1 with DHCP with WPA and 1 with DHCP with WEP) and 2 profiles for work (1 with static IP with WEP and 1 with DHCP with WEP).
So, here's a sample interfaces file, an accompanying script to detect the current environment based on MAC-addresses of accesspoints, a sample wpa_supplicant.conf file and a small script to bring the interfaces down before suspending/hibernating the computer (they're upped automatically on resume) so that if you change the location during this suspension, your laptop gets automatically a new IP as soon as you power it on again.
I'll assume that you know how to run commands (such as in a terminal) and edit files (with vi, gedit, etc.)
Installation:
Check if you have the packages wireless-tools & resolvconf. You should already have wireless-tools and resolvconf is needed if you want to set dns-suffices & nameservers. You can check this either via synaptic or running:
apt-cache showpkg resolvconf.
Review the MAC-addresses and other settings in the profiles file. The MACs can be found by calling
iwlist eth1 scanning under "Cell xx- Address:..." line
Only then copy the profiles file to /etc/network/profiles (make a backup of the old file first!!!)
Copy the script to /usr/local/bin/scan-wireless-mac-address.sh (or wherever you want to but don't forget to change the path for in the profiles file)
Review and copy the WPA-configfile it to /etc/wpa_supplicant.conf if you're using WPA.
[This may change] Copy the interface-down script to /etc/acpi/suspend.d/48-networking-down.sh (or whatever name you see fit)
I've included some optional commands such as pre-up, post-down, etc. I'll explain those shortly:
Normally if you want to connect to a WPA-protected AP (accesspoint) you should start the WPA_supplicant first, even just to connect to the AP (correct me if I'm wrong).
After you connect to some AP and got your IP, you can also copy a network-specific hosts file to /etc/hosts, which is simply a list of statically defined IP-numbers to avoid DNS lookups. This step could be done prior to connection, too, but it sounds better this way.
Whenever you bring down an interface, it has no sense anymore that wpa_supplicant runs in the background, so it's safe to kill it in a post-down line.
The profiles file:
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
# The loopback network interface
auto lo
iface lo inet loopback
# This is a list of hotpluggable network interfaces.
# They will be activated automatically by the hotplug subsystem.
#mapping hotplug
# script grep
# map eth1
# The primary network interface
auto eth1
mapping eth1
script /usr/local/bin/scan-wireless-mac-address.sh
map eth1 11:22:33:44:55:66 homedhcp
map eth1 11:22:33:44:55:66 home
map eth1 11:22:33:44:55:66 homealt
map eth1 22:33:44:55:66:77 workdhcp
map eth1 22:33:44:55:66:77 work
iface homedhcp inet dhcp
pre-up wpa_supplicant -B -i eth1 -c /etc/wpa_supplicant.conf -D ipw -q
post-up cp /etc/hosts.home /etc/hosts
post-down killall wpa_supplicant
#post-up ifconfig eth1 mtu 1300
iface home inet static
pre-up wpa_supplicant -B -i eth1 -c /etc/wpa_supplicant.conf -D ipw -q
post-up cp /etc/hosts.home /etc/hosts
post-down killall wpa_supplicant
network 192.168.100.0
address 192.168.100.186
netmask 255.255.255.0
gateway 192.168.100.1
dns-nameservers 11.22.33.44 55.66.77.88
dns-search my.domain
mtu 1300
iface homealt inet static
post-up cp /etc/hosts.home /etc/hosts
wireless-mode managed
wireless-essid alternate-wlan
wireless-key s:0123456789 open
network 192.168.100.0
address 192.168.100.186
netmask 255.255.255.0
gateway 192.168.100.1
dns-nameservers 11.22.33.44 55.66.77.88
dns-search my.domain
mtu 1300
iface workdhcp inet dhcp
#post-up ifconfig eth1 mtu 1300
wireless-mode managed
wireless-essid office-wlan
wireless-key-1 s:1234567890123 open
wireless-key 012345678990ABCDEF01234567 open
mtu 1300
iface work inet static
post-up cp /etc/hosts.work /etc/hosts
wireless-mode managed
wireless-essid office-wlan
wireless-key-1 s:1234567890123 open
network 10.11.11.0
address 10.11.11.169
netmask 255.255.255.0
gateway 10.11.11.1
wireless-key 012345678990ABCDEF01234567 open
#dns-search myworkdomain.com
#dns-nameservers 10.11.11.3
mtu 1300
iface eth0 inet dhcp
mtu 1300
# activating the following line increases bootup time!
# alternatively, one can decrease the timeout value in /etc/dhcp3/dhclient.conf
# auto eth0
The script to detect accesspoints, based on their MACs (no change needed):
#!/bin/sh
# this script finds out if an Access-Point with the given MAC address is reachable
# prints the profile (last parameter) out
# returns 0 if found, 1 if not
# should be called from /etc/network/interfaces like this:
# map eth1 11:22:33:44:55:66 homewlan
if [ `id -u` != 0 ]; then
echo "You have to run this script as root"
exit 1
fi
if [ "$1" = "" ] ; then
echo "You have to pass an interface name, e.g. eth1"
exit 1
fi
BINIWLIST="/sbin/iwlist"
if [ ! -x $BINIWLIST ]; then
echo "$BINIWLIST does not exist or is not executable!"
exit 1
fi
IF="$1"
which=""
while read IFACE MAC PROFILE; do
if [ "$which" ]; then continue; fi
echo -n "Checking if access-point $MAC is reachable... " >&2
if $BINIWLIST $IFACE scanning | grep "Cell" | grep $MAC > /dev/null 2>&1; then
echo "OK. Using profile $PROFILE" >&2
which="$PROFILE"
else
echo "" >&2
fi
done
if [ "$which" ]; then echo $which; exit 0; fi
exit 1
The script to bring the interfaces down (no changes needed):
#!/bin/bash
if [ -e /etc/network/interfaces ]; then
# bring down all interfaces
ifdown -a
fi
Sample WPA config file (change the SSID & key, more info under https://wiki.ubuntu.com/WPAHowto):
# Minimal /etc/wpa_supplicant.conf to associate with open
# access points. Please see
# /usr/share/doc/wpasupplicant/wpa_supplicant.conf.gz for more complete
# configuration parameters.
ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=0
eapol_version=1
ap_scan=1
fast_reauth=1
### Associate with any open access point
### Scans/ESSID changes can be done with wpa_cli
network={
ssid="cu"
scan_ssid=1
proto=WPA
key_mgmt=WPA-PSK
psk=00112233445566778899aabbccddeeff00112233445566 778899aabbccddeeff
}
I hope this helps someone. All suggestions and corrections are welcome.
EDIT: I've found this post from another Ubuntu user. Pretty much the same technique (using iwlist & interfaces file), just a bit different. Link: http://lists.ubuntu.com/archives/ubuntu-users/2005-April/028964.html
Peace and out