Enable Wake On Lan Across VLAN on Cisco Network

posted 6 Feb 2015, 04:47 by Tristan Self
Wake on LAN packets do not traverse routers (normally) so you need to configure your network to do this. There are some security implications you need to be aware of first, Cisco's document on it is a good read: http://www.cisco.com/c/en/us/support/docs/switches/catalyst-3750-series-switches/91672-catl3-wol-vlans.html

Also download Solarwinds Free Wake On LAN tool, its a good one to use to test this, it also has a command line to it as well.

So in this example we have the Wake On LAN controller PC on the IP address 172.26.40.22 in VLAN 240. The PC(s) we want to switch on are in the VLAN 244 subnet. We need to configure our core switch/L3 router with the below. This will allow the controller PC to send a request to the subnet to wake up the PC.

access-list 150 permit udp host 172.26.40.22 any eq 7
!
ip forward-protocol udp 7
!
interface vlan 240
 ip helper-address 172.26.47.255
!

interface vlan 244
 ip directed-broadcast 150
!

You need to ensure that the WOL tool you are using will send on udp port 7, if it doesn't the IP directed won't match.

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