Hi there,
I try to get WoL over subnets working. According to this guide, I need to add the broadcast address of the client networks on the server vlan interface.
WoL Server:
10.110.110.131
10.110.110.132
Client networks:
10.110.115.0
10.110.118.0
Switch with server vlan:
ip forward-protocol udp discard
interface Vlan110
ip helper-address 10.110.115.255
ip helper-address 10.110.118.255
Switch with client vlans
Extended IP access list 110
10 permit udp host 10.110.110.131 any eq discard
20 permit udp host 10.110.110.132 any eq discard
interface Vlan115
ip directed-broadcast 110
interface Vlan118
ip directed-broadcast 110
This is working fine, but with 400 subnets the helper list gets a bit long. Then I've read that I don't need the broadcast address on the server vlan, instead I use the WoL server IPs on the client subnet vlan as helper address and guess what: it works. My question is now: why and how does it work?
Switch with server vlan:
ip forward-protocol udp discard
Switch with client vlans
Extended IP access list 110
10 permit udp host 10.110.110.131 any eq discard
20 permit udp host 10.110.110.132 any eq discard
interface Vlan115
ip helper-address 10.110.110.131
ip helper-address 10.110.110.132
ip directed-broadcast 110
interface Vlan118
ip helper-address 10.110.110.131
ip helper-address 10.110.110.132
ip directed-broadcast 110
