How to set up Wake On LAN on ubuntu home server

I am thinking about setting up a home server, which could be used as file, print, web and whatsoever server, I was playing around for some time with a NAS device. The problem was, that it didn’t really satisfy my needs. One reason was that it was too loud. Another reason was, that the hardware had not enough power to do the things I wanted.

I took some old hardware, which was much more powerful than the NAS device to try if that could eventually fullfill my requirements. But as that hardware consumes more energy and home servers are often idle most of the day (at least in my case), the first feature I want the box to be capable of, is to support Wake On LAN. So it would be possible for me to put the box somewhere where I don’t need to have physical access to and just start it when I really need it and shut it down afterwards. That would be better for the environment and for my wallet, too.

Here’s how I managed it:

1. Check if the hardware supports WOL. If yes, enable it in the BIOS.
2. Install ethtool. You can do this by entering
   

   sudo apt-get install ethtool

   in a konsole window.

3. To check the settings, use the command ethtool {interface} where {interface} is the according interface. In my case the command is
   

   sudo ethtool eth0

   and the output looks like this:

   Settings for eth0:
           Supported ports: [ TP ]
           Supported link modes:   10baseT/Half 10baseT/Full
                                   100baseT/Half 100baseT/Full
                                   1000baseT/Half 1000baseT/Full
           Supports auto-negotiation: Yes
           Advertised link modes:  10baseT/Half 10baseT/Full
                                   100baseT/Half 100baseT/Full
                                   1000baseT/Half 1000baseT/Full
           Advertised auto-negotiation: Yes
           Speed: 100Mb/s
           Duplex: Full
           Port: Twisted Pair
           PHYAD: 0
           Transceiver: internal
           Auto-negotiation: on
           Supports Wake-on: pg
           Wake-on: d
           Current message level: 0x000000ff (255)
           Link detected: yes
   

   Important here are the lines starting with Supports Wake-on and Wake-on. The first tells us, which Wake-On-LAN modes the network interface supports and the second if/which mode is enabled. The man page of ethtool says:

   ...
          wol p|u|m|b|a|g|s|d...
                 Sets Wake-on-LAN options.  Not all devices support this.  The argument to this option is a string of characters specifying which options to enable.
                 p  Wake on phy activity
                 u  Wake on unicast messages
                 m  Wake on multicast messages
                 b  Wake on broadcast messages
                 a  Wake on ARP
                 g  Wake on MagicPacket(tm)
                 s  Enable SecureOn(tm) password for MagicPacket(tm)
                 d  Disable (wake on nothing).  This option clears all previous options.
   ...
   

   My interface supports modes p and g but at the moment, it is disabled (Wake-on: d).

4. Enable WOL using sudo ethtool -s eth0 wol g. Now sudo ethtool eth0 shows Wake-on: g.
5. Test if it works. To do this, you need another computer with a tool which supports to send the MagicPacket(tm). You could e.g. install wakeonlan with a sudo apt-get install wakeonlan on the computer which wants to wake the server. Additionally, you need the MAC address of your server’s network interface. You can get that with a ifconfig eth0 on your server. That will result in something like this:

   eth0      Link encap:Ethernet  Hardware Adresse XX:XX:XX:XX:XX:XX
             inet6-Adresse: XXX::XXX:XXXX:XXXX:XXXX/64 Gültigkeitsbereich:Verbindung
             UP BROADCAST RUNNING MULTICAST  MTU:1500  Metrik:1
             RX packets:0 errors:0 dropped:0 overruns:0 frame:0
             TX packets:14 errors:0 dropped:0 overruns:0 carrier:0
             Kollisionen:0 Sendewarteschlangenlänge:1000
             RX bytes:0 (0.0 B)  TX bytes:3204 (3.2 KB)
             Interrupt:16
   

   To test, if it works, shutdown the server. Then try a wakeonlan XX:XX:XX:XX:XX:XX where XX:XX:XX:XX:XX:XX is the address in line one of the output of ifconfig-command above. If it worked, the first step is done.

I don’t know, if it is necessary to do the following steps on every computer which wants to be woken up, but in my case, the setting of the ethtool command was not permanent(you could check this by a anew sudo ethtool eth0 or just try to wake a second time). If it is not permanent:

6. add the line
   

   ethtool -s eth0 wol g

   to the file /etc/rc.local.

7. reboot
8. try again if it works (for me it does)

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