The paper says that in order for the Wake on LAN frame to get through
routers the Manager station (the one that wakes devices up) must send a UDP
IP directed broadcast. That answers the question as to whether it's an IP
frame or not. Normally it's just an Ethernet frame, but to get through
routers the Manager must be configured to send it as an IP frame. That
makes sense.
Priscilla
At 04:58 PM 6/16/01, Shawn Goodson wrote:
>All,
> If it helps here is a link that has some good information on WOL. There
>is a link to AMD in the online references, that has a white paper that
>breaks down actual frame, and discusses network and platform issues with
>WOL. One section describes how the engineers at IBM used the subnet directed
>broadcast for WOL. We don't incorporate the feature at our sites. But I
>might try to tinker with it in the lab after reading the posts (peaked my
>interest).
>
>http://gsd.di.uminho.pt/jpo/software/wakeonlan/mini-howto/wol-mini-howto.htm
>l#toc4
>
> Aloha
> Shawn
>
>
>----- Original Message -----
>From: "Priscilla Oppenheimer"
>To:
>Sent: Friday, June 15, 2001 4:26 PM
>Subject: Re: wake on lan [7:8792]
>
>
> > The "no ip directed-broadcast" command is for IP, as you can tell. If you
> > don't see that command in the running config, then ip directed broadcasts
> > are presumably being forwarded. A directed broadcast is one that comes
>from
> > a device on one segment and is destined to all devices on another
network,
> > for example 10.0.0.1 sending a frame to 172.16.255.255.
> >
> > But it sounds like ip directed broadcasts won't do you any good because
> > Wake on LAN isn't an IP packet.
> >
> > To make the router forward a broadcast that has no network layer you
would
> > have to turn on bridging.
> >
> > Priscilla
> >
> >
> > At 06:40 PM 6/15/01, khramov wrote:
> > >As far as I know WOL layer 2 broadcast, it does not have an IP field.
> > >That is the main problem.
> > >What is the command to look up if direct-broadcast is already enabled on
>the
> > >router?
> > >Thanks,
> > >
> > >Priscilla Oppenheimer wrote:
> > >
> > > > One other thought: The article that Patrick referenced implies that
>you
> > > > could enable directed broadcasts. The default on modern routers is no
> > > > directed broadcasts but you could disable that. It's not recommended
>for
> > > > security reasons, but if you want to do it the command is "no ip
> > > > directed-broadcast."
> > > >
> > > > http://esupport.ca.com/public/sdo_shipit/infodocs/7065.asp
> > > >
> > > > But you have to find out what the server or whatever is sending to
>wake
> > up
> > > > the stations. You are troubleshooting in the blind until you find out
> > what
> > > > it is sending.
> > > >
> > > > Is it an IP packet?
> > > > Is it a UDP packet?
> > > > Is it just a MAC packet?
> > > > Is it a broadcast? At the MAC and IP layers?
> > > >
> > > > Priscilla
> > > >
> > > > At 05:58 PM 6/15/01, Priscilla Oppenheimer wrote:
> > > > >The "ip helper" command might help.
> > > > >
> > > > >Also use the "ip forward-protocol" command to forward the Wake on
LAN
> > > > >broadcast and the "no ip forward-protocol" command to not forward
>other
> > > > >broadcasts.
> > > > >
> > > > >You would have to check the documentation to see if this would work
>for
> > > > >sure. Let us know how it goes! Thanks.
> > > > >
> > > > >Priscilla
> > > > >
> > > > >
> > > > >
> > > > >At 03:31 PM 6/15/01, khramov wrote:
> > > > > >I think that wake on lan sends out a broadcast with FFFFF... in
the
> > > > > >destination field.
> > > > > >May be because it a layer 2 broadcast it is not passing the
>packets.
> > > > > >Can I configure a router to pass layer 2 broadcasts? And if I can
>is
> > > > > >there a way to
> > > > > >control the broadcast so that only wake on lan packets would pass?
> > > > > >Thanks
> > > > >
> > > > >
________________________
Priscilla Oppenheimer
http://www.priscilla.com
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=8861&t=8792
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