From owner-freebsd-questions Tue Feb 20 23:37:55 2001 Delivered-To: freebsd-questions@freebsd.org Received: from palrel1.hp.com (palrel1.hp.com [156.153.255.242]) by hub.freebsd.org (Postfix) with ESMTP id F2C1437B401 for ; Tue, 20 Feb 2001 23:37:51 -0800 (PST) (envelope-from klui@cup.hp.com) Received: from hpcuhe.cup.hp.com (hpcuhe.cup.hp.com [15.0.80.203]) by palrel1.hp.com (Postfix) with ESMTP id 5B38FFC4; Tue, 20 Feb 2001 23:37:51 -0800 (PST) Received: from localhost (klui@localhost) by hpcuhe.cup.hp.com (8.9.3 (PHNE_18979)/8.9.3 SMKit7.02) with ESMTP id XAA07141; Tue, 20 Feb 2001 23:37:44 -0800 (PST) Date: Tue, 20 Feb 2001 23:37:44 -0800 (PST) From: Ken Lui To: Lowell Gilbert Cc: freebsd-questions@freebsd.org Subject: Re: Question about arp for wakeonlan In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On 19 Feb 2001, Lowell Gilbert wrote: > > So do I specify my local router's IP but my home PC's ethernet > > address? OK, I did this but I lost connection with my work machine. > > I'm unsure of how to set up a "proxy" entry in arp. > > Proxy arp is a terrible hack, and breaks the IP layering model > something fierce. Nonetheless, there are occasions when people find > it useful; however, those situations involve a router (which does the > proxying) which is directly connected to both the host for which the > router is proxying and the hosts receiving the proxy packets. It > doesn't sound like that's what's happening in your case, unless the > default router for your home machine is somehow the same machine as > the default router for your work machine. > > You indicated that you want to do wake-on-LAN, but that this only > works if the router has a current ARP entry for the machine you're > waking. This makes sense; the machine won't wake up on broadcasts, or > wake-on-LAN would never work at all, so the router has to be able to > do a unicast for the wake packet. This is only possible if the router > has an ARP mapping, so you're depending on the router keeping a valid > ARP entry for the host; if the host is sleeping, this is only possible > with a static entry in the router's ARP table. So you need to do the > ARP command on the router, not either of the end machines. > Alternatively, you could get another machine on the same link to send > the "wake" packet for you, and make sure that *it* has the static ARP > entry for the sleeping machine. > > I hope that this explanation is sufficient to get you going. If not, > it's likely that you simply don't have the access to be able to do > what you want. Lowell, Thanks for taking the time to explain arp to a network newbie like myself. Although your reply indicated that it will not work, I did get wake on LAN to work over the WAN even after the arp entry has expired on the (in my case Cisco) router. My two machines--both FreeBSD--are on different subnets connected by different routers using different netmasks. Once the arp entry expired, I could no longer wake my work machine (for example) from home via wakeonlan . I then tried to add a proxy on my home system via the command: arp -s pub I had to do this twice because the first time, I got the error of "cannot intuit interface index and type for ". But when I issued the command a second time, the command was successful and I could use wakeonlan to wake up my work machine. I would speculate that issuing arp -s pub followed by a wakeonlan command would wake my home PC from work. Regards, Ken To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message