ARP and Wake On LAN

[dacruzer1]

We have been having some problems with WOL and someone suggested that if we increase the arp timeout on the router it would solve the issue with WOL.  I have my doubts but can anyone tell me if that is true or not.

Thanks

Alfred

[Rolf Fischer]

Hello Alfred,

what kind of WoL setup are you using?

The "traditional"  Magic Packet with broadcast as destination doesn't need ARP at all.

However, if you use unicast destinations and the clients are in another subnet, an ARP entry is indeed needed to build the Layer 2 header of the packet. After 4 hours an ARP entry ages out per default, so you may have to find a way to avoid this.
I think, most times broadcast is used because with unicast the sleeping clients have to have a valid IP-address (DHCP binding).
So it really depends on how your WoL works, more precisly what kind of packets are send.

Hope that helps

Rolf