Question service port, internal port


Aug 12, 2014
I'm following this thread ( to set up a PC so it can be remotely waken up. Step 2 says I need to create a new rule to forward port 9 to the PC.

In my router's (TP-LINK TL-WR940N) setup page, it has "service port" and "internal port". I need to enter a value for both. I guess the internal port is 9. What about the service port? What should I enter there?
There are all these article written by people who do not actually use this stuff. They might set it up run it and it magically works and they write up their blog and try to get ad revenue. Problem is they do not let everything sit for a few hours and then try again and discover it won't work. The ARP entry times out in the router and the packets are discarded.

There is no such thing as wake on WAN. The instructions you see on many of these sites make a number of invalid assumptions. The first is that you can send data directly to the PC mac address. This may or may not work depending on how closely the bios follows the standard.

A wake on lan packet is a packet sent to the BROADCAST mac address that contains the mac address of the pc to be woken inside the packet in a special format.

You will notice there is no discussion of IP addresses or port numbers etc. This is a layer 2 protocol not designed to pass over a router.

So I would first recommend you forget about WoL and use the sleep options in your machine. Even though the machine is in sleep mode most remote access software will still fully wake the machine.

Other wise you have much more complex things to figure out than how to configure port forwarding on your router.

The first step is to figure out how to put in a static arp entry which almost no router has that ability.

You must put a static arp mapping some unused ip from your lan to the broadcast mac address. You then need to put in port forwarding rules for this unused ip address. Your software application must be smart enough to put the proper mac address into the packet and then send it to the external IP.

WoL is extremely unreliable since you have to be very careful how you shut the machine down. Microsoft has all kinds of proprietary suspend modes. It is just simpler to use the power save options on the pc and not bother with WoL.