Network Problems of Ethernet?

At a school I used to attend, we were told by our instructors that connecting our laptops to the network via ethernet was against their computer use policy, and apparently resulted in some tech person coming to the classrooms on a few occasions.

My question pertains to reasons why ethernet might be prohibited for students.

I can't imagine it would be security related, because of the abundance of ethernet ports around the buildings, including the clients in the computer labs and such that are connected by ethernet. If it has to with some kind of network interference, are there any situations where some kind of mitigation really isn't possible?

Clarification: Lab computers were connected with ethernet, and we could use them without issue. For laptops, we were required to use Wifi.

bitflips

Posted 2013-02-20T04:35:45.717

Reputation: 405

What did you use instread of ethernet? – Paul – 2013-02-20T04:43:23.963

Sorry about that, for the lab computers we did use ethernet, and for laptops we were required to use wireless. I briefly mentioned the ethernet on the lab computers but I'll update it to clarify. The whole thing was they didn't want us plugging in with laptops. – bitflips – 2013-02-20T04:47:22.103

From a recent question, I guess maybe they didn't want you unplugging the lab computers to use their Ethernet cables. – Dan D. – 2013-02-20T04:48:48.113

That's what I assumed was the most likely case, but I wonder how that becomes an issue for the network people. I'm not familiar enough with ethernet networking to know if it's hardware dependent, like if the unexpected hardware of the laptop was causing issues or something. – bitflips – 2013-02-20T04:52:43.440

Are the laptops provided by the school, or your own? – Paul – 2013-02-20T06:25:16.440

Answers

I can guess a few possible reasons - is that the wired network might have been kept seperate from the wireless reasons, possibly using a different subnet or authentication method. The other is well, they simply don't want you to - especially if someone disconnects a more important device for a quick fix. It happens.

AUP/Computer usage policy isn't always technically driven. It could be as simple as 'We can't be bothered to keep an eye on the wired network' or "We don't want people using these jacks cause we say so"

Journeyman Geek

Posted 2013-02-20T04:35:45.717

Reputation: 119 122

1Sounds about right -- there could be one more issue -- most wifi networks comes with a "client isolation" option, which when enabled prevent laptops to see each other -- that is a great way of making sure that virus from one private laptop does not spread around the school -- wired network usually does not come with that option unless you have really high end and expensive switches. – Soren – 2013-02-20T05:38:13.233

@Soren - you can do the same thing on the wired connection as well: using secondary VLANs. – Sudipta Chatterjee – 2013-02-20T06:41:08.000

@SudiptaChatterjee: in which case they'd have to mark which lan point is on which vlan. Its a lot less messier than just handing the students a wireless key and telling them NOT to touch the wired connections – Journeyman Geek – 2013-02-20T06:42:30.037

@SudiptaChatterjee: I think that is what I said -- VLANs are only availble on higher end switches, and even then VLANs does not provide client isolation -- the client isolation is what you get by default when you are on a public wifi such as in starbucks – Soren – 2013-02-20T19:32:06.203