What’s wrong with this picture?
Yeah, the blue-stripe and green-stripe wires should be interchanged. Turns out the Link indicators on both ends lit up just fine, but no bits made it across the wire. Took quite a while to figure that one out, alas.
Turns out I was moving that router upstairs to get a better signal for folks out in the driveway and snaking the cable through the only suitable (i.e., existing) hole in the floor required cutting the molded-in-place connector off, then crimping a new one on. Both you and I know those wires must cross, but in the excitement of pushing all those wires into the connector, well … so it goes.
A useful explanation, including crossover and POE cable arrangements, lives there.
I did wrap silicone tape around the cable and connector butt for strain relief.
Memo to Self: just verifying the colors on the existing cable sometimes isn’t good enough!