ejohansson.se » network

Wake on LAN with Debian

Erik Johansson — Thu, 31 Dec 2009 13:45:20 +0000

To enable Wake on LAN on a Asus P5E-V motherboard under Debian you can do the following. Since I have a Asus motherboard, that’s the only one I’ve tested, but except from the BIOS (which may differ a bit), the instructions should be the same for all motherboards/NIC that supports Wake on LAN.

In the BIOS, enable “Power on by PCIE device”.

In Linux, first install ethtool and then check that Wake on LAN is supported by running the following command:

root@host$ ethtool eth0
...
        Supports Wake-on: g
        Wake-on: g
...

The output should contain a ‘g’ to indicate that the device can be woken by sending it a “magic packet”.

Enable Wake-on by running:

root@host$ ethtool -s eth0 wol g

Since this command must be run on every boot, add it to /etc/rc.local.

root@host$ cat /etc/rc.local
...
ethtool -s eth0 wol g
exit 0

As the last step we must make sure that halt doesn’t disable the network device. This is done by adding this line to /etc/default/halt:

NETDOWN=no

We also need the MAC address to send the magic packet to.

root@host$ ifconfig eth0
eth0      Link encap:Ethernet  HWaddr 00:1e:8c:cf:d0:bb  
...

Then shutdown the computer. On an other computer, install e.g. wakeonlan and run:

user@other$ wakeonlan 00:1e:8c:cf:d0:bb

The computer should now start.

Wii and Netgear WNR834B

Erik Johansson — Sat, 20 Dec 2008 17:44:23 +0000

I recently had a lot of problems connecting my Nintendo Wii wireless to my girlfriend’s Netgear router (WNR834B). The router was configured to use WPA-PSK [TKIP] + WPA2-PSK [AES] with a fairly long pass phrase (ASCII characters). It worked very well with my iBook (Mac OS X) and worked most of the time with my girlfriend’s laptop (Windows Vista). But it seemed like Windows used the WPA variant instead of WPA2. It just didn’t connect when forcing it to use WPA2. And the Wii would only connect if we turned encryption off. Not acceptable!

We tried many things to get the Wii to connect, without any success. In a last attempt we tried changing the pass phrase to a 64 characters long hexadecimal pass phrase. That did the trick. Both the Wii and both laptops now connect without any problem. So if you are having problems connecting your Wii to the wireless network, try changing the pass phrase to consist of hexadecimal characters (0-9, A-F) only. For WPA/WPA2 it must be exactly 64 characters long.

Simulate a slow network

Erik Johansson — Fri, 24 Mar 2006 08:47:10 +0000

Kurt Pfeifle has written an interesting article about how to simulate a slow network. I haven’t been able to test it yet since CONFIG_NET_SCH_NETEM wasn’t enabled in my kernel config. But as soon as I have recompiled my kernel, I will.

More information on netem’s homepage.