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.

My first impression was that my O2 Router was being useless and not passing new IPs to their server… but on closer inspection there is a reason for this… in 3-4 months of use of O2 Broadband, my IP has never changed! I’m a bit of a security freak, so I switch the router off every evening when I finish with the PC… so it has to request an IP on a daily basis and seems to always get the same one.

Just an observation, but from my use at least, it appears O2 is effectively handing out static IPs, even to its dynamic IP users!

I say this having just spent near-on a week of frustration wondering why the BeachyUK server hated me and refused to send my mails! After finally finding some time to sit down and diagnose the issue, I’m really irritated that it seems my wonderful new Broadband provider (O2) have taken it upon themselves to block Port 25, to encourage me to send mail via their servers.

Quite apart from the fact that the choice of server I send my mail through is my own decision, I fail to see the benefit here to O2, they’re actually encouraging me to put more load on their SMTP server rather than use my own… hmm, maybe they have an interest in the mails I’m sending

So for anyone out there with the same issue with O2 Broadband (or another overly obsessive ISP), if you have control of your server, just change your mail sending port to an alternative port (and do the same on the server that’s receiving the mail, and hey presto, you’re back in business, despite the efforts of your ISP!)… otherwise, you’ll need to use your ISP’s relaying SMTP mail server to send mails, or you can use your mail servers SSL port, and send using SSL.

One finally thing actually… searching the Internet, I found a lot of sites (in fact, even O2′s help section), saying to use “smtp.o2.co.uk” for outgoing mail if you’re an O2 Broadband customer, this however is wrong for this use. The afore-named domain is for O2 mail users. If you’re looking to relay mail on behalf of your own domain you need to use “relay.o2broadband.co.uk” (no authetication required, and the mail will be seen to come from your domain name).