Hello all, like everyone else I've been having issues with the 2704n and port forwarding... specifically if the device you want to forward to is appearing as unknown xx:xx:xx:xx then you can set up a rule, and it works, but anytime something else connects to your network and comes up as 'unknown' (which can be any number of devices, even ones that normally appear named, e.g. a sleeping ipod/iphone etc etc etc) it starts using that device to forward to instead...
well, you can observe the behaviour - if you set up your rule while there is ONLY ONE UNKNOWN in your system you can probably get it to work, you may need to set your device to get IP from the router as DHCP, and you may need to make that a static assignment in 192.168.1.254/expert_user.html
About seven eighths of the way down in the xml you'll see the portmapping elements, one for each line of your rule. See how your device is shown with a name of unknown- xx:xx:xx:xx:xx, but the mac address is in a different line, and the ip address is in another different line, at the moment they're all correct.
If at this point another 'unknown' joins your network, and you refresh that dump page, you'll see that the device name in the portmapping has remained the same, but the mac address and the ip address are now for the new unknown device. So your rule is at this point knackered.
How to fix?
I think it's just a case of copying your working (ie the earlier) cfg into a file, removing the space at the start and the stats at the end, making a subtle alteration, saving it and uploading it again using 192.168.1.254/updatesettings.html - a procedure that has been outlined in several places on this forum.
The change I made that seemed to work (so far) is just to write an actual name value into the devicename attribute for each instance of the rule, e.g. <X_BROADCOM_COM_DeviceName>mydevicename</X_BROADCOM_COM_DeviceName>
I think that's all that's needed to stop the 2704n messing the rule up when a different 'unknown' joins the network, and i think the change will stick, you don't have to keep relying on the file. The devicename you wrote now shows up in the plusnet port forwarding page on the row for your rule (but not in the assign-to-device dropdown). It's not called 'unknown' anymore, and so the rule no longer gets the mac/ip addresses of other 'unknown' devices.
I think that's all there is to it, but for the sake of completeness I should add - My device (an ip camera) *did* very very occasionally show up with a name other than 'unknown' in the home page list of devices.. so that is the name I used.. I don't know if that matters, I think not, probably.. 99% of the time the camera does not register a name.
Also in the xml file where it lists the static IP addresses to dish out via DHCP, all my records seem to show a device name of UNKNOWN. In my efforts to get things working I changed that value to the same name too. But I very much doubt it makes any difference.