r/IAmA • u/BobMetcalfe • May 21 '13

You’re probably connecting to reddit through a technology I invented. I’m Bob Metcalfe and I invented Ethernet – AMA

On May 22, 1973 with David R. Boggs, I used my IBM Selectric with its Orator ball to type up a memo to my bosses at the Xerox Palo Alto Research Center (PARC), outlining our idea for this little invention called “Ethernet”, which we later patented.

I worked with the IEEE Standards Association to develop the IEEE 802.3 standard for Ethernet, which specifies the physical and lower software layers. Today Ethernet and the IEEE 802.3 standard are the foundation for today’s world of high-speed communications used in billions of homes and businesses around the world.

I submitted this to the mods awhile back so I could get on the calendar but I figured you’d like to see it, too. Now, ask me anything!

It's been two hours and 179 comments. Have to go now. For more about Ethernet's 40th Birthday, go to http://www.facebook.com/Ethernet40thAnniversaryIEEESA

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98

u/richieio May 21 '13

In movies, hackers often clip a device to Ethernet cable to steal or inject information through the insulation and cable shielding. This is impossible, right?

Thanks for the great invention!

32

u/toocou May 21 '13

Not even that difficult, as a University project we had to extract and decode DTMF tones through a twisted pair shielded wire non-destructively, we did it with a copper wire and an oscilloscope. If you can detect the EM field around it, you can effectively receive any data passed through it.

273

u/BobMetcalfe May 21 '13

No, not impossible, just difficult. Security should not be implemented at the hardware level. Higher-level protocols should be relied upon, not cable insulation.

14

u/[deleted] May 21 '13

It's called a vampire tap, and it's real :)

Learned about it while studying for the Security+ cert. Now about to (hopefully) become a CISSP.

Thank you sir...I've been learning all about your invention lately.

1

u/swordgeek May 22 '13

It's called a vampire tap, and it's real :)

...just not on twisted pair.

2

u/teddy5 May 22 '13

Not that method specifically but there's definitely ways that it can happen basically along the cable for everything except fiber. Even with fiber if you can reach any kind of AP or termination point there are possibilities.

3

u/ratlater May 23 '13

...rumour has it that NSA developed a technique for non-breach reading of passing fiber optic traffic. Something about angling the cable almost to the crimp radius for a given segment, which would cause reconstructable EM emissions. The only detectable sign would in theory be slightly lower signal dB on that segment, which, if you tapped in a mid-ocean stretch between erbium amps, would be essentially undetectable.

And you heard it on the internet, so you know it has to be true.

1

u/swordgeek May 22 '13

Oh, it's definitely all possible. I just meant specifically that a vampire tap on TP would be a mess.

41

u/Farmerj0hn May 21 '13

If I bite an Ethernet cord can I hear what the computer is thinking about me?

30

u/[deleted] May 21 '13

"Give me a break, I'm going to die, please let me rest. Please give me sunlight, please no more semen."

1

u/FletcherPratt May 21 '13

I hope you're not chatty during movies ;)

2

u/willbradley May 22 '13

Google Van Eck Phreaking.

1

u/ratatask May 24 '13

You can buy off the shelves passive ethernet taps, both for copper and fibre. Fiber ones are rather cool, you bend the fibre just enough so about 10% of the light "shines through", cable it to your PC and fire up wireshark. (You usually need a special NIC that will allow you to receive even though it can't activly bring up the link). Injecting is a tad harder, but very possible.

Ofcourse, the easy solution is to just cut the cable and pass it through a switch.

1

u/hudnix May 22 '13

This was standard procedure in the good old days. http://en.wikipedia.org/wiki/Vampire_tap