CentOS Wake On Lan 기능 활성화

저도 시스템 2대에 centos 5.5 설치하고서는 WOL이 되지 않았었는데,
- centos 4.5 에서는 "ethtool -s eth0 wol g" 로 잘 사용하고 있었습니다 -
찾아보니 레드햇 기술문서에 내용이 있네요.

델 PC에서는 해보니 잘 되네요.
(HP 서버에서는 안 되는데.. xen kernel도 아닌데 왜 안 될까요..)

https://access.redhat.com/kb/docs/DOC-33077 -> 계정이 있어야 볼 수 있어서 퍼왔는데, 그래도 되는지 모르겠네요..

Wake On LAN may not work with Xen hosts in Red Hat Enterprise Linux 5 Article ID: 33077 - Created on: Apr 28, 2010 2:20 PM - Last Modified: Jun 1, 2010 3:59 AM

Issue
WOL [Wake On LAN] does not work after Xen kernel shutdown.
After configuring a Xen-based host system to wake up when a "magic packet" is received, the system may not restart when the magic packet is sent.

Environment
Red Hat Enterprise Linux 5
Xen virtual machine management

Resolution
The workaround is to add the following line to /etc/rc.d/init.d/xend:
/etc/xen/scripts/network-bridge stop
before the line:
/usr/sbin/xend stop
This assumes that xend is configured to use the network-bridge script to configure the network devices for use with xen guests. If you use another script (such as network-bridge-bonding), then issue the appropriate command to de-configure the bridge before xend shuts down.

Warning: De-configuring the Xen network bridge will cause the system to stop functioning if the root file system is located on a network file system (NFS, iSCSI, etc.)

Root Cause
Adding a network device to a bridge can make it incapable of responding to the Wake-On-LAN (WOL) magic packet. Shutting down the Xen bridge before halting the system allows the network device to respond to WOL packets, but will also temporarily disrupt network communication through the network devices connected to the Xen bridge. When network communication is disrupted, connections to network-based file systems such as NFS or iSCSI will be lost. If the root file system is on such a network-based file system, then the system will stop functioning properly when network communications are disrupted as a result of the Xen bridge shut-down process.

Diagnostic Steps
Configure a Red Hat Enterprise Linux 5 (RHEL 5) Xen Host (Dom0) to enable WOL on the physical network device. This can be done temporarily by issuing a command similar to the following:
ethtool -s eth0 wol g
or made permanent by adding a line to /etc/sysconfig/network-scripts/ifcfg-eth0 similar to the following:
ETTHTOOL_OPTS="wol -g"
and then rebooting the system.
Shut down the system
From another system, send a WOL magic packet to the system that was just shut down. The shut-down system will not re-start.