What's this about?
Moving files between two machines over a direct Ethernet cable, with no switch, router or configuration in between.
Why does this work without a switch?
Because Ethernet is point-to-point at the physical layer, and modern network interfaces do auto-MDI-X — they detect that the other end is another host rather than a switch and swap their transmit and receive pairs automatically. That is why the crossover cable, once a required piece of every network engineer's bag, quietly stopped being necessary. Assign both ends an address in the same subnet and you have a working two-node network.
Why is it worth noticing?
HN 157 points, 168 comments
- Extremely high comment count for a simple technique, because everyone has a war story about the crossover cable era.
- Practically relevant: a direct link is often the fastest way to move a large amount of data between two machines you physically have.
- Also the safest way, in that the data never touches a network anyone else is on.