Difference between revisions of "Wake-on-LAN"
m (Great article! ethtool needs sudo; works with Ubuntu 12.0; alternative auto lo; asus mobo tested ok.)
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== Sending 'magic packet' to wake up your mythbox ==
== Sending 'magic packet' to wake up your mythbox ==
You will need a wake-on-lan client to send 'magic packets' over your network. First, determine the MAC address of the machine you
You will need a wake-on-lan client to send 'magic packets' over your network. First, determine the MAC address of the machine you to power on:
Revision as of 10:46, 20 November 2013
If you have a network card that supports wake-on-lan (wol), you can powerup your mythbox by sending it a 'magic packet' over the network.
- 1 Setting up
- 2 Sending 'magic packet' to wake up your mythbox
- 3 Password 'protection'
- 4 Wake-on-LAN supported but just won't wake up
- 5 Tested with
- 6 Useful links
First, find out whether your network card supports wol:
# sudo ethtool eth0 Settings for eth0: Supported ports: [ TP MII ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full Supports auto-negotiation: Yes Advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full Advertised auto-negotiation: Yes Speed: 100Mb/s Duplex: Full Port: MII PHYAD: 1 Transceiver: internal Auto-negotiation: on Supports Wake-on: pumbg Wake-on: d Current message level: 0x00000001 (1) Link detected: yes
The 'g' in Supports Wake-on: pumbg indicates that wake-on-lan by using a 'magic packet' is indeed supported. Next, you need to make sure that wake-on-lan support is enabled in the BIOS (although, this does not seem to be necessary for my motherboard). In addition, you need to tell your network card to enable wake-on-lan:
# sudo ethtool -s eth0 wol g
When you run `sudo ethtool eth0` again you will see that "Wake-on: d" (disable; wake on nothing) has changed to "g" (wake on magic packet)
Since after rebooting Wake-on will be reset, you will want to add this setting somewhere in your boot up.
To make this setting permanent edit
/etc/network/interfaces, in the
auto eth0 section (or you might have an
auto lo section) add at the end:
To make this setting permanent edit /etc/rc.local:
# nano -w /etc/rc.local
ethtool -s eth0 wol g above the 'exit 0' line.
Now turn off you mythbox and send it a 'magic packet'.
Sending 'magic packet' to wake up your mythbox
You will need a wake-on-lan client to send 'magic packets' over your network. First, determine the MAC address of the machine you want to power on:
Turn off your mythbox and from another computer execute the following command (replacing the MAC address with the one you just found). I used a wake-on-lan client from Sourceforge.
$ wol 00:4F:49:07:0B:5F
Via Python one-liner
Maybe not as clean, but works on all systems where Python is available, replace the '\x00\x1A\x92\x9D\x69\x85' with the numbers of your backend's MAC address:
# python -c "import socket; s=socket.socket(socket.AF_INET, socket.SOCK_DGRAM); s.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1); s.sendto('\xff'*6+'\x00\x1A\x92\x9D\x69\x85'*16, ('<broadcast>', 7));"
Send automatically from a frontend
By adding one or two scripts into a remote frontend, it will automatically start the backend, and then wait until the backend is ready to accept a client connection. Ideally the frontend and backend would boot concurrently, however that's difficult to arrange without building a special environment (e.g. to boot rapidly from flash memory), so the practical solution is simply to use an /etc/init.d script in the frontend, and wait while the frontend and backend boot serially.
The purpose of the first script is to issue the WOL packet as early as possible. If the overall bootup time is not considered to be an issue, this script can be omitted and the wakeonlan command can be issued from the script which runs from the user's auto-started sessions (called mythfestart.sh, further down). These scripts use 'wakeonlan' from Ubuntu package repos, but wol or ether-wake would work just as well.
/etc/init.d/wol: #! /bin/sh # MAC address of backend SERVER_MAC=xx:xx:xx:xx:xx:xx # case "$1" in start) # Issue wakeonlan at intervals until our own network interface # is active and the magic packet is successfully sent. # until /usr/bin/wakeonlan $SERVER_MAC > /dev/null 2>&1 ; do sleep 1 done ;; *) esac exit 0
After the above script has been placed in /etc/init.d/ (and marked executable with chmod +x ..), it can be made to run at bootup by issuing:
sudo update-rc.d wol defaults
Now we need a script which waits until the backend is ready to accept client connections, before starting mythfrontend. That way, the frontend will start cleanly without any error panels such as "no UPnP backends found", etc. This script can be added to the user's autostarted sessions (in place of the normal 'mythfrontend' script).
/usr/bin/mythfestart.sh: #! /bin/bash # IP address of backend SERVER_IP=xxx.xxx.xxx.xxx # SERVER_MAC=xx:xx:xx:xx:xx:xx # Could optionally send a wakeup packet here, if # a) it is decided that the early-running script above is not needed, or # b) to cover the rare case that backend was shutting down when first one sent # # Use mythTV status port as backend connectivity test until [ -n "`telnet $SERVER_IP 6544 |grep -i connected`" ]; do sleep 3 done # start frontend mythfrontend & exit 0
Both scripts must of course be made executable with chmod +x <script-filename>
Wake-on-lan has a SecureON password feature. Here's an example of how to use ethtool and wol with SecureON (note that the password contains 6 hexadecimal numbers):
# ethtool -s eth0 wol g sopass 11:22:33:aa:bb:cc $ wol --passwd=11-22-33-aa-bb-cc 00:4F:49:07:0B:5F
Wake-on-LAN supported but just won't wake up
At this writing, the Marvell Gigabit Ethernet controller on the Asus A8V and some other motherboards, using skge driver under Debian Etch may not wake at all while connected at Gigabit speeds to a Gigabit switch. The same hardware may wake correctly when shutdown with Windows in a dual-boot system.
A variety of workarounds have been suggested, from modifying the halt binary to using the NIC at 100 Mbps speeds, to placing calls to ethtool in various startup/network/shutdown scripts, but the simplest path to solution is probably to disable the motherboard network controller in BIOS and replace with a known-good PCI Gigabit NIC (such as the US Robotics 7902 Gigabit NIC).
Wake On LAN, Fedora 11 and Realtek RTL8111/8168 (etc)
This chip seems to be pretty common, along with a lot of problems getting WOL to work... I suspect this will apply to the following NICs chips
RTL8111B/RTL8168B/RTL8111/RTL8168 RTL8111C/RTL8111CP/RTL8111D(L) RTL8168C/RTL8111DP/RTL8111E RTL8105E
Finally, after much headache, this is the fairly simple solution (based on much crawling around on the web and some considerable testing)... Go to the Realtek Site, download the driver from there (http://www.realtek.com.tw/downloads/downloadsView.aspx?Langid=1&PNid=13&PFid=5&Level=5&Conn=4&DownTypeID=3&GetDown=false) Follow the instructions in the README and make and install yourself a new kernel mod (this will be r8168).
Now, edit /etc/modprobe.d/blacklist.conf and add
# NIC Kludge Stop r8169 loading so that r8168 will blacklist r8169
this stops the r8169 module loading after reboot, this is the one that ships with the kernel, and WOL won't work (except for physical activity), which means it will happily use your shiney new r8168 module instead.
It also appears to be necessary to place the following lines into /etc/init.d/halt
/usr/sbin/ethtool -s eth0 wol g # This sets the WOL options on the NIC you may wish to use different ones sleep 10 # Apparently this is necessary
The above lines need to be the penultimates ones, just above
exec $command $HALTARGS
Some motherboards allow a large set of events to wake-up the machine via ACPI. These can be toggled via
/proc/acpi/wakeup. Examples of ACPI wakeup events related to Wake-on-LAN:
- 'LAN0', 'LANC' - The ethernet card
- 'P0P2', 'PCI0' - The PCI bridge may need to be allowed to wakeup your machine before WOL works. You can find out which is your PCI bridge by matching the first column of
lspcioutput with the last column of
One-liner to enable a wakeup event (ex: LAN0):
# grep 'LAN0.*enabled' < /proc/acpi/wakeup >/dev/null || echo LAN0 > /proc/acpi/wakeup
/proc/acpi/wakeup is a legacy system. It is in the process of being split into
/sys/devices/[..]/power/wakeup per device. Use
echo enabled > power/wakeup on each device node you want to use to wake up the machine. Shortcuts may be available, like
/sys/class/net/eth0/device/power/wakeup for your eth0 network device..
- Epia M10k with Fedore Core 4
- M2NPV-VM with Ubuntu 10.04
- MacPro 1,1 with Arch Linux
- Asus M3N78-EM mobo with Mythbuntu 12.04
- http://ahh.sourceforge.net/wol/ (wake-on-lan client + additional information)
- http://dag.wieers.com/packages/wol/ (wol packages for RedHat and Fedora)
- http://www.die.net/doc/linux/man/man8/ethtool.8.html (man page for ethtool)
- http://www.sourceforge.net/projects/gkernel/ (gkernel package that contains ethtool)