eth4

Anyone have any ideas what the gigabit "eth4" link is all about on Sky D-Link routers?

Jan 1 00:00:07 kernel: eth4 Link UP 1000 mbps full duplex

As far as I can see there are 4 ethernet ports, eth0 to eth3, so I'm unsure where this eth4 fits in. Almost gets my hopes up thinking there may be a gigabit switch in there somewhere.

If its a re-badged D-Link router cant you get the actual model off it and look on the D-Link site? Is there an actual port on the back of the router for a eth4 port? Perhaps you can crack it open and solder one on? Although I can see the benefit if its just one port. The 100mbit offered by the other four will still only work at 100 unless there is also a firmware hack to go along with it!
Would be nice to know the details though!

Yeah, it's just idle curiously more than anything else. It's a DSL-2640S, a re-badged DSL-2640B I think, although perhaps there have been hardware modifications as well as software.