LAN network question (restricted access)

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LAN network question (restricted access)

Postposted on Wed Jun 04, 2014 9:00 am

Hello,

I have no idea if I'm at the right place here with my question (COMPLETE computer newbie).

Anyway, I started at a new workplace (public school), and technology-wise, it's... not very advanced, let's put it that way.
So in some rooms, we have those LAN-access points. As our school doesn't have any laptops, we are required to bring our own. Now the problem is that I can't access the LAN-network. I plug-in my cable, but it won't give me access. So I guess that the school restricted their access to the LAN network... Could someone please explain to me how that works and if there is a way around it? Because it's very annoying, especially if I need access to the internet for one of my classes.

Should someone want to answer me: Please dumb it down, I only speak idiot :P

Thank you! :)
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Re: LAN network question (restricted access)

Postposted on Wed Jun 04, 2014 9:31 am

There are several ways that it could be done, but first a couple of basic questions:

1. Does your laptop work other places while plugged-in (most laptops use Wireless these days, not a plugged-in/Ethernet connection)?
2. Does it show you have a link (when you plug it in, there should be lights on your laptop)
3. If this is a Windows laptop, what do you see when you go into Control Panel|Network and Internet|Network and Sharing Center? Is there a question mark or exclamation point between you and the Internet?

To answer your question more directly, yes there are ways to block access at the network level. The most popular would be to use a technique known as port security, where the traffic is filtered by allowable addresses. If this is done you would need to give the IT folks the MAC (not to be confused with Macintosh) address of your computer. They should be able to help you find that as well....
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Re: LAN network question (restricted access)

Postposted on Wed Jun 04, 2014 9:32 am

Most educational establishments have a MAC-address-based lockdown on network ports, which means that only devices that are "permitted" to be on the network will work when plugged in. Optionally the "unused" ports may not actually be physically connected to anything at the other end, although this is unlikely.

If you're working at said school, chances are they'll allow your machine to connect if you just ask them. There's no real way to do it without asking though :).
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Mentawl
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Re: LAN network question (restricted access)

Postposted on Wed Jun 04, 2014 9:39 am

There's all kinds of things it could be, including ports not hooked up, 802.1x Port Based Network Access Control, MAC address locking, authenticated proxies etc etc etc.

You need to go ask as the others have said.
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Re: LAN network question (restricted access)

Postposted on Thu Jun 05, 2014 5:13 pm

Mentawl wrote:Most educational establishments have a MAC-address-based lockdown on network ports, which means that only devices that are "permitted" to be on the network will work when plugged in. Optionally the "unused" ports may not actually be physically connected to anything at the other end, although this is unlikely.

If you're working at said school, chances are they'll allow your machine to connect if you just ask them. There's no real way to do it without asking though :).




notfred wrote:There's all kinds of things it could be, including ports not hooked up, 802.1x Port Based Network Access Control, MAC address locking, authenticated proxies etc etc etc.

You need to go ask as the others have said.



THESE ^

Based on past experience, there's probably a cisco switch onsite that's using port security. Go talk to the admins, and they can diagnose, and add you to the allowed list.
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Re: LAN network question (restricted access)

Postposted on Thu Jun 05, 2014 5:19 pm

Jness wrote:Should someone want to answer me: Please dumb it down, I only speak idiot :P

Thank you! :)

When you plug the Ethernet cable into your lappy, do you get link lights showing/blinking on the lappy's Ethernet jack (required by Ethernet standards)? If yes, it's an access control problem. If no, it's an air gap (unconnected wall jack) problem.
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Re: LAN network question (restricted access)

Postposted on Fri Jun 06, 2014 3:50 pm

Captain Ned wrote:
Jness wrote:Should someone want to answer me: Please dumb it down, I only speak idiot :P

Thank you! :)

When you plug the Ethernet cable into your lappy, do you get link lights showing/blinking on the lappy's Ethernet jack (required by Ethernet standards)? If yes, it's an access control problem. If no, it's an air gap (unconnected wall jack) problem.



Off-hand, I can think of a few scenarios where the port LEDs are green and *look* like it's passing traffic, but there's no connectivity:

Duplex mismatch
Failure beyond the intermediary device (like a patch panel or an uplink port on the switch)
Spanning Tree issues
Misconfigured DTP
blocked by an ACL/VACL, or port-security

I'm guessing since we haven't heard back from Subby that they went to their IT/IS department and got it resolved.
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Re: LAN network question (restricted access)

Postposted on Fri Jun 06, 2014 4:23 pm

Hey, how about a static IP assigned to the NIC in the laptop?
I have nothing more to say about that.
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Re: LAN network question (restricted access)

Postposted on Fri Jun 06, 2014 4:47 pm

Xylker wrote:Hey, how about a static IP assigned to the NIC in the laptop?



Jness would have to already know the proper subnet and mask, and make sure there isn't a conflict. If it's a MAC based restriction, they'd have to spoof the correct 48bit address.

Much easier to just go to IT and say "Here. Make it go." :P
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