Configuration Wake On LAN

[tonyp8581]

Hi,

I followed the procedure with the following document to configure WOL,

http://www.cisco.com/en/US/products/hw/switches/ps5023/products_configuration_example09186a008084b55c.shtml

The WOL server is on vlan 1 and Workstation is on vlan 2

WOL IP address vlan 1

10.10.1.1

Workstation IP address vlan 2

10.10.2.1

When the WOL server sends the magic packet with destination 10.10.2.255, the workstation wakes up.  Fine so far,

however, when the WOL server sends the magic packet to destination 255.255.255.255, the workstation doesn't wake up.

Do I need to add other command line on my 3560 to let the full broadcast work ??

Thanks !

[Giuseppe Larosa]

Hello Tony,

255.255.255.255 is the broadcast address and it is not routable by definition, so it cannot reach vlan 2 if received on vlan1.

you should convert it to something routable like 10.10.2.255 a directed broadcast is routable and can reach vlan 2 from vlan1.

an ip helper-address 10.10.2.255 under interface vlan1 may do the trick, but as explained in the document you need to take care of the UDP port in use to tune

ip forward-protocol command

Hope to help

Giuseppe

[tonyp8581]

Hi Giuseppe,

Thanks for your reply.

As I mentioned on my first post, the workstation does wake up when my destination is 10.10.2.255.  I'm using ZEN to send the magic packet, by default it uses destination 255.255.255.255.  I would prefer using this type of broadcast address since I have several vlan's.

About your comment "255.255.255.255 is the broadcast address and it is not routable by definition".

Doesn't a DHCP client use an all subnet broadcast to find a DHCP server.  Adding the ip helper-address command into the 3560, it converts the broadcast into a unicast.  Basically, that's what i'm trying to do with the wol server.  i want to use the full subnet broadcast.  Hence, the validity for my initial question.

Thanks !

[paolo bevilacqua]

As indicated before by Giuseppe.

You need to use ip helper-address with a directed broadcast address.

[Giuseppe Larosa]

Hello Tony,

>>

since I have several vlan's.

then you need multiple ip helper address commands one for each IP subnet pointing to the directed broadcast address of each one

the WOL will be sent out on each IP subnet including the one where the client is connected.

multiple ip helper address are supported

Hope to help

Giuseppe

[Richard Burts]

Having recently done a configuration for WOL I have a clarification and a suggestion.

Tony says:"Adding the ip helper-address command into the 3560, it converts the broadcast into a unicast." The helper-address can turn the local broadcast into a unicast or it can turn it into a directed broadcast which is what Tony wants to do. So Giuseppe is correct in suggesting one or more helper-addresses be configured.

In addition to taking care of the forward protocol Tony will also need to assure that the directed broadcast will be accepted by the receiving router/switch interface. For a long time the default in Cisco IOS has been to disable directed broadcast (which is regarded as a potential security issue). So Tony will need to enable directed broadcast on the VLAN 2 interface and any other interfaces which will receive the directed broadcast.

HTH

Rick

[tonyp8581]

Hi Giuseppe,

Looking at my configuration closely, I noticed that ip helper-address was missing.  Adding

it solved my issue.

Thanks for your help.  Including everybody else that joined this discussion.

Tony