Setting up a System w/ Wake-on-LAN and VNC?

andrebsd asks: "I'd like to make myself some sort of webpage where I could startup my system with 'Wake on Lan', and once it is started, use VNC to login. Once I'm done doing what I need the system for I would then like to shut it down again. I'm wondering how one might go about putting something like this together. VNC has various scripts for making that part work, but I haven't seen any scripts that can function as a 'Power on/Power off' button for a webpage. Thanks to anyone with any way of doing this." While there are helpful reference for Wake-on-LAN tools, how would you integrate all of these into a coherent system? How might one keep such a system (relatively) secure?

Comments

WOL isn't very hard.

[duffbeer703]

You'll need to lookup the precise specifications for WOL. Basically you simply send the MAC address three times to the target machine over UDP. Then the NIC wakes the computer up.

It's not very difficult to do this with a perl script or something similar that can be integrated into a web page.

Another alternative that may interest you if your target computer has access to a phoneline is "Wake on Ring". Some BIOS vendors (Abit was one) allow a modem to power on a PC after a specified number of rings.

Re: it's not IP, so it won't get routed

[graf0z]

I have to correct myself: You may use ANY packet You want (IP, IPX, whatever), as long as it

• contains the "magic sequence"
• is contained in a valid ethernet frame
• is address to the target's MAC- or a multicast address (including broadcast).

Because of the handshake You cannot use TCP, but any UDP or ICMP (ping!) packet including the magic would do it. It has to pass the firewall (if any). The dest address could be

• unicast if the last router has a static arp entry for the dest
• broadcast if the last router forwards broadcast packets
• multicast if You have a multicast routing path from You into the last subnet.

Read AMD whitepaper and a howto.

/graf0z.