Wake on WAN – Reason why it only works for 15 mins or so

Since signing up personally with O2 Broadband and getting the O2 Wireless box iii, I’ve been wanting to setup Wake on WAN (aka Wake on Internet) to enable me to use my desktop computer while away from home on business or holiday, while satisfying my eco-urge not to leave my PC on all the time.

Wake on WAN was the perfect solution, enabling me to shutdown the computer and simply leave my router switched on. At the press of a virtual button, I could then “wake” (startup) the desktop computer, use it via Remote Access, and shut it down again, ready to be woken again if required at a later date.

Setting Up Wake on LAN/WAN/Internet
There are tons of guides for this across the Internet, so I won’t go into much detail here, port 7 or 9 generally needs forwarding from the router to your PC, and your BIOS needs to be setup to accept the packets. (Note: If you will need to forward further ports for any applications you intend to use once your computer has booted (e.g. Port 3389 for Microsoft Remote Desktop)).

Working intermittently – The problem and solution
This is the section you’ve probably arrived here to read…
The problem: You’ve setup Wake on WAN, and you’ve tested it while sat at your computer… perfect, no issues at all. But about 15 mins later (after shutting down the computer) it stops reacting to magic packets over the WAN.
After swearing profusely at my PC (which doesn’t help I hasten to add), and finding no help from Google, which just found similarly pee’d people, it struck me. When the packets stop working over the WAN they still work over the LAN. This is simply because your router has flushed the ARP table, and will therefore no longer broadcast to your PC based on a WAN request.
The solution: Rather simply therefore, place a permanent entry in the ARP table of your router, and ensure your router has a dedicated internal IP for your machine.

Adding a static ARP on O2 Wireless box iii

  • Telnet to your router (in Windows, open Command Prompt, and type “telnet”. Then “o 192.168.1.254”, or a different IP if your router is at a different IP (“o” means open connection to)
  • Login with the SuperUser id (Default details: User: SuperUser Password: O2Br0ad64nd – note: Case-sensitive (capital O and B), and underlined characters are numbers zero, six and four)
  • Once logged in, type “menu” and hit return
  • Use your arrow keys to navigate to “ip”, then hit return
  • Use your arrow keys to navigate to “arplist”, then hit return. This will show you the current ARP table. You may see an entry for your PC in there that is marked “dynamic”, this means it will be flushed at the next flush if the PC is switched off.
  • Now use your arrow keys to navigate to “arpadd”, then hit return
  • Hit return to edit the field you’re in, (intf initially) Enter:
    intf: LocalNetwork
    ip:{ENTER INTERNAL IP OF YOUR PC – e.g. 192.168.1.14}
    hwaddr:{ENTER MAC ADDRESS OF YOUR PC – e.g. 00:11:03:7f:01:23
  • Hit TAB to move to “OK”, then hit return. (If you get an error “Failed to add ARP entry”, you can try again, but you are likely to find it easier to do with the machine you are configuring switched off, so there is no dynamic entry for it. i.e. configure from a different machine)
  • Now you need to save the ARP, otherwise at next restart of the router, you’ll lose your new static route, and be back to square one!
  • TAB to cancel to leave the menu, then hit return.
  • Type “saveall” and hit return.
  • Done – type “exit” and hit return, and then “q” and return to leave the Telnet session.

3 thoughts on “Wake on WAN – Reason why it only works for 15 mins or so”

  1. Thank you so much! You seem to be the only person on the entire internet who addressed my exact problem! I had Wake on WAN working, but it would stop working if the device was left off for a few minutes. Now it boots fine! My XBMC-live setup salutes thee.

    • Pleased to hear it, thanks for that Stuart! It was driving me mad, so I’m glad to have been able to save you too much of the same.

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