Difference between revisions of "Netcfg Tips"
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Insert the following line to the network profile(s) which will kill all connected sshd sessions upon a network restart/stop: | Insert the following line to the network profile(s) which will kill all connected sshd sessions upon a network restart/stop: | ||
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=== rfkill (enable/disable radio power) === | === rfkill (enable/disable radio power) === |
Revision as of 17:09, 12 February 2013
Template:Article summary start Template:Article summary text Template:Article summary heading Template:Article summary wiki Template:Article summary wiki Template:Article summary end
Contents
- 1 Enabling WOL
- 2 Using jumbo frames
- 3 Clean logouts for users connected via sshd
- 4 rfkill (enable/disable radio power)
- 5 Execute commands before/after interface up/down
- 6 Intermittent Connection Failure
- 7 Per-interface configuration
- 8 Output hooks
- 9 ArchAssistant (GUI)
- 10 Netcfg Easy Wireless LAN (newlan)
- 11 wifi-select
- 12 Passing arguments to dhcpcd
- 13 Using dhclient instead of dhcpcd
- 14 Configuring a bridge for use with virtual machines (VMs)
- 15 Adding multiple IP addresses to one interface
- 16 Adding static routes
Enabling WOL
Enabling WOL can be accomplished using a POST_UP statement in the profile.
POST_UP='/usr/sbin/ethtool -s eth0 wol g'
Using jumbo frames
Insert the following line to the network profile(s) which require a non-standard MTU value:
POST_UP='/usr/sbin/ip link set eth0 mtu 4000'
The above example is using a 4k jumbo frame.
Clean logouts for users connected via sshd
Insert the following line to the network profile(s) which will kill all connected sshd sessions upon a network restart/stop:
PRE_DOWN='/usr/bin/pkill sshd'
rfkill (enable/disable radio power)
netcfg can enable/disable radio for wireless cards equipped with software control of radio. For wireless cards with hardware switches, netcfg can detect disabled hardware switches and fail accordingly.
To enable rfkill support, you need to specify what sort of switch the wireless interface has; hardware or software. This can be set within a profile or at the interface level (/etc/network.d/interfaces/$INTERFACE
; see #Per-interface configuration).
RFKILL=soft # can be either 'hard' or 'soft'
For some kill switches the rfkill entry in /sys
is not linked to the interface and the RFKILL_NAME
variable needs to be set to the contents of the matching /sys/class/rfkill/rfkill#/name
.
For example, on an Eee PC:
RFKILL=soft RFKILL_NAME='eeepc-wlan'
On a mid-2011 Thinkpad:
RFKILL=hard RFKILL_NAME='phy0'
net-auto-wireless
daemon requires an interface level configuration of rfkill or it will not start./sys/class/rfkill/rfkill#
entries with different names on every switch. Something like this will work in such cases (wifi-only solution!):
/etc/network.d/interfaces/wlan0
RFKILL=hard RFKILL_NAME=`cat /sys/class/rfkill/rfkill*/name 2> /dev/null || echo ""`
Execute commands before/after interface up/down
If your interface requires special actions prior/after the establishment/closure of a connection, you may use the PRE_UP
, POST_UP
, PRE_DOWN
, and POST_DOWN
variables.
For example, if you want to configure your wireless card to operate in ad-hoc mode but you can only change modes when the interface is down, you could use something like this:
PRE_UP="ip link set wlan0 down; iwconfig wlan0 mode ad-hoc"
Or if you want to mount your network shares after a successful connection, you could use:
POST_UP="sleep 5; mount /mnt/shares/nexus/utorrent 2>/dev/null"
Sometimes you may want to run something from netcfg with another user:
POST_UP="su -c '/you/own/command' username"
exit 0
at the end. Alternatively you can add || true
to the end of the command that may fail.eval
statement. Profile and interface variables like ESSID
are available for use, but must be escaped so that their evaluation is deferred to the eval. The easiest way to do that is to use single quotes. For example: PRE_UP='echo $ESSID >/tmp/essid'
will evaluate correctly, regardless where the PRE_UP
command is.Intermittent Connection Failure
Some driver+hardware combinations drop associations sometimes. Use the pre and post commands to add/remove the driver and use a script like the following to fix the current connection:
/usr/local/bin/netcfgd
#!/bin/bash log() { logger -t "$( basename $0 )" "$*" ; } main() { local host while sleep 1; do [[ "$( netcfg current )" = "" ]] && continue host=$( route -n | awk '/^0.0.0.0/ { print $2 }' ) ping -c1 -w10 $host && continue log "trying to reassociate" wpa_cli reassociate ping -c1 -w10 $host && continue log "reassociate failed, reconfiguring network" netcfg -r $( netcfg current ) done } exec 1>/dev/null [[ $EUID != 0 ]] && { log "must be root"; exit 1; } for cmd in wpa_cli ping netcfg; do ! which $cmd && { log "can't find command ${cmd}, exiting..." exit 1 } done log 'starting...' main
Per-interface configuration
Configuration options that apply to all profiles using an interface can be set using /etc/network.d/interfaces/$INTERFACE
. For example:
/etc/network.d/interfaces/wlan0
This is useful for wpa_supplicant
options, rfkill switch support, pre/post up/down scripts and net-auto-wireless
. These options are loaded before profiles so that any profile-based options will take priority.
/etc/network.d/interfaces/$INTERFACE
may contain any valid profile option, though you are likely to use PRE_UP
/DOWN
and POST_UP
/DOWN
(described in the previous section) or one of the options listed below. Remember that these options are set for all profiles using the interface; you probably do not want to connect to your work VPN here, for instance, as it will try to connect on every wireless network!
WPA_GROUP - Setting the group of the wpa_ctrl interface WPA_COUNTRY - Enforces local regulatory limitations and allows use of more channels WPA_DRIVER - Defaults to wext, may want nl80211 for mac80211 devices
Output hooks
netcfg has limited support to load hooks that handle output. By default it loads the arch
hook which provides the familiar output that you see. A syslog logging hook is also included. These can be found at /usr/lib/network/hooks
.
ArchAssistant (GUI)
A Qt-based netcfg front-end called ArchAssistant exists. It proposes to manage and connect/disconnect profiles from a system tray icon. Automatic wireless detection is also available. This tool is particularly useful for laptop users.
Links:
- archassistantAUR in the AUR
- archassistant on kde-apps.org
There is also a relatively new GUI for netcfg on qt-apps.org that does only network configuration. You can find it here.
Netcfg Easy Wireless LAN (newlan)
newlan is a mono console application that starts a user-friendly wizard to create netcfg profiles; it also supports wired connections.
Install the newlanAUR package from the AUR.
newlan
must be run with root privileges:
# newlan -n mynewprofile
wifi-select
There is a console tool for selecting wireless networks in "real-time" (in NetworkManager fashion) called wifi-select. The tool is convenient for use in Internet cafés or other places you are visiting for the first (and maybe the last) time. With this tool, you do not need to create a profile for a new network, just run wifi-select wlan0
as root and choose the desired network.
The tool is currently packaged as wifi-select and is available in the official repositories.
wifi-select does the following:
- parses
iwlist scan
results and presents a list of networks along with their security settings (WPA/WEP/none) using dialog - if user selects network with existing profile -- just use this profile to connect with netcfg
- if user selects a new network (for example, a Wi-Fi hotspot), wifi-select automatically generates a new profile with corresponding
$SECURITY
and asks for the key (if needed). It uses DHCP as$IP
by default - then, if the connection succeeds, the profile is saved for later usage
- if the connection fails, the user is asked if he or she wants to keep generated profile for further usage (for example to change
$IP
to static or adjust some additional options)
Links:
- Forum thread related to development of wifi-select
- wifi-select on GitHub
Passing arguments to dhcpcd
For example, add this to the desired profile:
DHCP_OPTIONS='-C resolv.conf -G'
The above example prevents dhcpcd from writing to /etc/resolv.conf
and setting any default routes.
Speed up DHCP with dhcpcd
By default, dhcpcd
confirms that the assigned IP address is not already taken via ARP. If you are confident that it will not be, e.g. in your home network, you can speed up the connection process by about 5 seconds by adding --noarp
to DHCP_OPTIONS
:
DHCP_OPTIONS="--noarp"
If you never want dhcpcd
to perform this check for any connection, you can globally configure this by adding the following line to /etc/dhcpcd.conf
:
noarp
Using dhclient instead of dhcpcd
To use dhclient instead of dhcpcd, simply add DHCLIENT=yes
to the desired profile.
Configuring a bridge for use with virtual machines (VMs)
To configure a bridge named br0 with a static IP:
/etc/network.d/br0
INTERFACE="br0" CONNECTION="bridge" DESCRIPTION="bridge br0 static" BRIDGE_INTERFACES="eth0" IP='static' ADDR='10.0.0.10' GATEWAY='10.0.0.1' DNS='10.0.0.1'
To configure a bridge named br0 with a dhcp IP:
/etc/network.d/br0
INTERFACE="br0" CONNECTION="bridge" DESCRIPTION="bridge br0 dhcp" BRIDGE_INTERFACES="eth0" IP='dhcp'
Then add the corresponding bridge name to your NETWORKS=(...)
in /etc/conf.d/netcfg
.
It can be brought up by calling it directly, or by restarting net-profiles
.
netcfg br0
rc.d restart net-profiles
Adding multiple IP addresses to one interface
If you want to assign multiple IP addresses to 1 specific interface, this can be done by issuing the relevant ip
command in a POST_UP
statement (which as the name suggests will be executed after the interface has been brought up). Multiple statements can be separated with a ;
. So if you for example would want to assign both 10.0.0.1 and 10.0.0.2 to interface eth0; the config would look something among the lines of:
/etc/network.d/multiple_ip
INTERFACE="eth0" CONNECTION="ethernet" IP='static' ADDR='10.0.0.1' POST_UP='ip addr add 10.0.0.2/24 dev eth0'
Adding static routes
When wanting to configure static routes, this can be done by issuing the relevant ip
command in a POSTUP
statement (which as the name suggests will be executed after the interface has been brought up). Optionally, a PRE_DOWN
statement can be added to remove said routes when the interface is brought down. Multiple statements can be separated with a ;
. In the below example we'll route 10.0.1.0/24 over interface eth1 and then remove the route when the interface is brought down.
/etc/network.d/static_routes
INTERFACE="eth1" CONNECTION="ethernet" IP='static' POST_UP='ip route add 10.0.1.0/24 dev eth1' PRE_DOWN='ip route del 10.0.1.0/24 dev eth1'
Bluetooth tethering with pand
You can create a netcfg profile for easy tethering with your Bluetooth enabled device by using the regular "ethernet" connection and managing the pand connection in the PRE_UP and POST_DOWN hooks. Assuming an already paired device with address 00:00:DE:AD:BE:EF
:
/etc/network.d/tether
CONNECTION="ethernet" DESCRIPTION="Ethernet via pand tethering to Bluetooth device" INTERFACE="bnep0" BTADDR="00:00:DE:AD:BE:EF" PRE_UP="pand -E -S -c ${BTADDR} -e ${INTERFACE} -n 2>/dev/null" POST_DOWN="pand -k ${BTADDR}" IP="dhcp"
Then, either as root or using sudo, execute:
# netcfg tether
To bring the interface down and un-tether:
# netcfg down tether