Ethernet Switches & Routers

Brocade FastIron Wake-On-LAN (WOL) Configuration

by gfcm on ‎04-18-2011 07:24 AM (500 Views)

We tried to implement Wake-On-LAN with a Brocade FastIron Router across several subnets. You can find below our experiences, please do not hesitate to share your knowledge or add your comments.

Background information

Wake-on-LAN (WOL) has been used  for years as a way for network administrators to turn on PCs remotely. It works by creating and issuing a  specially formatted network packet (often referred to as a "magic"  packet, and typically generated via a software utility) containing a  target PC's MAC address.

WOL is  based on the principle that when the PC shuts down, the NIC  still  receives power, and keeps listening on the network for the magic  packet to arrive. This magic packet is mostly based on UDP. In our case  we will use the utility from SolarWinds that will send a UDP packet on  port (7) to trigger the wake up of a remote machine.

Equipment used

  • FastIron FCX that runs FCXR07100a.bin (Router)
  • FastIron FCX that runs FCXS07100a.bin (Switch)
  • Freeware Wake-On-LAN utility from SolarWinds

Considerations

Before deploying WOL across several subnets, first ensure your desktop can be waken remotely.

  • Check your BIOS settings and ensure Wake-On-LAN is enabled
  • Check your NIC Advanced Settings and ensure that Magic & Directed Packets are accepted
  • Connect your WOL server and your desktop/laptop client to the same VLAN
  • Invoke Wake Up PC from SolarWinds utility
  • If the PC wakes up you can go further and configure it across several subnets

Network Diagram

WOL_diagram.png

Configuration

  • Router (inter-VLAN)

!

vlan 10 name server_vlan by port
  tagged ethe 1/1/10

  untagged ethe 1/1/1
  router-interface ve 10
!

vlan 20 name user_vlan20 by port

  tagged ethe 1/1/10
  router-interface ve 20
!

vlan 30 name user_vlan30 by port
  tagged ethe 1/1/10
  router-interface ve 30
!

!
ip forward-protocol udp echo
interface ve 10
  ip address 192.168.10.1 255.255.255.0

  ip helper-address 1 192.168.20.255

  ip helper-address 2 192.168.30.255

!
interface ve 20
  ip address 192.168.20.1 255.255.255.0

!
interface ve 30
  ip address 192.168.30.1 255.255.255.0
!


  • Switch

!
vlan 10 name server_vlan by port
  tagged ethe 1/1/10
  untagged ethe 1/1/1
!
vlan 20 name user_vlan20 by port
  tagged ethe 1/1/10
  untagged ethe 1/1/2
!
vlan 30 name user_vlan30 by port
  tagged ethe 1/1/10
  untagged ethe 1/1/3
!

Explanation

As soon as your inter-VLAN routing is configured correctly, there are  only 2 commands to add so that your machines on different subnets/VLANs  can be waken remotly by a WOL server. The Brocade FastIron Router does not forward by default requests for UDP applications. You can enable forwarding support for a specific port (forward-protocol). Then you have to specify the port used by your application. In our case, SolarWinds uses UDP packets on port 7 (echo).

The second step is to configure an helper address on the VLAN of the WOL server to be able to join the subnet of your clients. The aim is to foward packets from the WOL server to each client subnet. Thus you have to specify the broadcast address of each client network to make it work. This is the only way to send a packet to a machine that is asleep. Indeed, in this situation, the PC will not be able to answer to ARP requests, since it does not own its IP at this time.

  • Specify the protocol (udp) and port (7) to be forwarded:

ip forward-protocol udp echo


  • Enable forwarding of WOL packets to clients

ip helper-address 1 192.168.20.255