# Plugging office ethernet cable into personal laptop, but can't connect -- what's missing technically
**URL:** https://boards.straightdope.com/t/plugging-office-ethernet-cable-into-personal-laptop-but-cant-connect-whats-missing-technically/573828
**Category:** Factual Questions
**Created:** [March 7, 2011, 8:33pm UTC](https://boards.straightdope.com/t/plugging-office-ethernet-cable-into-personal-laptop-but-cant-connect-whats-missing-technically/573828 "2011-03-07T20:33:04Z")
**Posts on this page:** 13
**Page:** 1
### Author:  [@drastic\_quench](https://boards.straightdope.com/u/drastic_quench)
#### Post date: [March 7, 2011, 8:33pm UTC](https://boards.straightdope.com/t/plugging-office-ethernet-cable-into-personal-laptop-but-cant-connect-whats-missing-technically/573828/1 "2011-03-07T20:33:04Z")
My office computer (worked provided) gets online just fine, so why can’t I use the same cable to get my laptop online? Sorry, I’m not IT savvy. Is their network not recognizing my pc?
I can log on wifi, but I’m curious as to the technical aspects of why this won’t work.
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### Author:  [@yoyodyne](https://boards.straightdope.com/u/yoyodyne)
#### Post date: [March 7, 2011, 8:38pm UTC](https://boards.straightdope.com/t/plugging-office-ethernet-cable-into-personal-laptop-but-cant-connect-whats-missing-technically/573828/2 "2011-03-07T20:38:46Z")
Generally a work network will be configured to not allow unknown devices to connect for security reasons.
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### Author:  [@Doug\_K](https://boards.straightdope.com/u/Doug_K)
#### Post date: [March 7, 2011, 8:57pm UTC](https://boards.straightdope.com/t/plugging-office-ethernet-cable-into-personal-laptop-but-cant-connect-whats-missing-technically/573828/3 "2011-03-07T20:57:21Z")
They probably have their wireless network isolated from the wired network. Some schools and hospitals have wireless “guest networks” that connect to the internet but don’t give access to printers, network shares, or other resources. No reason a business couldn’t do the same thing.
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### Author:  [@Keeve](https://boards.straightdope.com/u/Keeve)
#### Post date: [March 7, 2011, 9:04pm UTC](https://boards.straightdope.com/t/plugging-office-ethernet-cable-into-personal-laptop-but-cant-connect-whats-missing-technically/573828/4 "2011-03-07T21:04:49Z")
I’m one of the IT guys at my place, and it is as the above have said. Find out who is in charge of your network and ask, “Do I have the proxy settings right?”
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### Author:  [@Lobsang](https://boards.straightdope.com/u/Lobsang)
#### Post date: [March 7, 2011, 9:06pm UTC](https://boards.straightdope.com/t/plugging-office-ethernet-cable-into-personal-laptop-but-cant-connect-whats-missing-technically/573828/5 "2011-03-07T21:06:31Z")
I have been checking back to this thread waiting to see what the proper technical answer is. I am vaguely aware that there’s a process involved in doing this. you basically ‘join’ the network with your computer/laptop, once on the network you don’t log into the machine using its locally stored user/profile. You log onto the network using a user/account stored on the network.
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### Author:  [@yoyodyne](https://boards.straightdope.com/u/yoyodyne)
#### Post date: [March 7, 2011, 9:20pm UTC](https://boards.straightdope.com/t/plugging-office-ethernet-cable-into-personal-laptop-but-cant-connect-whats-missing-technically/573828/6 "2011-03-07T21:20:21Z")
> [@Lobsang](#):
>
> I have been checking back to this thread waiting to see what the proper technical answer is. I am vaguely aware that there’s a process involved in doing this. you basically ‘join’ the network with your computer/laptop, once on the network you don’t log into the machine using its locally stored user/profile. You log onto the network using a user/account stored on the network.
The account you log into the computer with is a separate issue from getting online. The laptop network card may not be set up for DHCP. The network may not be set up for DHCP. The DHCP server may not give out addresses to unregistered network cards. The router security may not allow unknown devices.
It could be many things, it’s best to talk to IT.
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### Author:  [@Kingfisher](https://boards.straightdope.com/u/Kingfisher)
#### Post date: [March 8, 2011, 12:40am UTC](https://boards.straightdope.com/t/plugging-office-ethernet-cable-into-personal-laptop-but-cant-connect-whats-missing-technically/573828/7 "2011-03-08T00:40:53Z")
It sounds like your work network may be running a [Network Access Control](http://en.wikipedia.org/wiki/Network_Access_Control) system which is typical for a large organization.
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### Author:  [@AaronX](https://boards.straightdope.com/u/AaronX)
#### Post date: [March 9, 2011, 2:02am UTC](https://boards.straightdope.com/t/plugging-office-ethernet-cable-into-personal-laptop-but-cant-connect-whats-missing-technically/573828/8 "2011-03-09T02:02:05Z")
I say it’s the MAC address. Each computer has a unique code, and the network only allows a certain list of codes, which doesn’t include your laptop. You can spoof this address and you’ll be able to connect.
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### Author:  [@Askance](https://boards.straightdope.com/u/Askance)
#### Post date: [March 9, 2011, 2:12am UTC](https://boards.straightdope.com/t/plugging-office-ethernet-cable-into-personal-laptop-but-cant-connect-whats-missing-technically/573828/9 "2011-03-09T02:12:35Z")
The other possibility is that you don’t have your machine set up to acquire an address via DHCP but have it hard-coded. Next time you’re plugged into they network open up a Dos command line and do
ipconfig /all
and paste the results in here, please.
Also, is your home machine used wired when at home or just via wireless? It’s possible your wired connection is disabled, or simply faulty.
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### Author:  [@Crown\_Prince\_of\_Irony](https://boards.straightdope.com/u/Crown_Prince_of_Irony)
#### Post date: [March 9, 2011, 2:36am UTC](https://boards.straightdope.com/t/plugging-office-ethernet-cable-into-personal-laptop-but-cant-connect-whats-missing-technically/573828/10 "2011-03-09T02:36:10Z")
I know in our company, the internet connection is managed through the [Active Directory](http://en.wikipedia.org/wiki/Active_Directory) system (Windows’ network directory which manages users/systems and what resources they can connect to). This system not only allows access per login name/password, but also checks asset IDs/tags to ensure that the system is company owned.
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### Author:  [@HomeBrewer](https://boards.straightdope.com/u/HomeBrewer)
#### Post date: [March 9, 2011, 12:31pm UTC](https://boards.straightdope.com/t/plugging-office-ethernet-cable-into-personal-laptop-but-cant-connect-whats-missing-technically/573828/11 "2011-03-09T12:31:59Z")
Since you’ve asked for the technicals behind what you’re experiencing I’d say you’re best off asking your IT guys, as there are any number of ways to keep your computer from connecting and to explain each would be quite a discussion. For instance, where I work we have a system in place that administratively shuts down the switch port if a different MAC address is sensed. Perhaps you could get the MAC off your work PC and spoof it on a VM (virtual machine) to see if that gets you connected? Assuming of course that once the port has shut down it will reopen automatically for the ‘right’ device.
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### Author:  [@Doug\_K](https://boards.straightdope.com/u/Doug_K)
#### Post date: [March 9, 2011, 1:29pm UTC](https://boards.straightdope.com/t/plugging-office-ethernet-cable-into-personal-laptop-but-cant-connect-whats-missing-technically/573828/12 "2011-03-09T13:29:31Z")
It’s almost certainly possible to get your machine on using some combination of MAC spoofing, and matching proxy and network settings. HOWEVER no one here knows if or how much your company cares about outside computers. If they do care, the more work you have to do to connect the more likely they are to consider it malicious when you get caught. If this isn’t just an academic question you need to ask your IT people before trying anything.
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### Author:  [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)
#### Post date: [March 9, 2011, 2:49pm UTC](https://boards.straightdope.com/t/plugging-office-ethernet-cable-into-personal-laptop-but-cant-connect-whats-missing-technically/573828/13 "2011-03-09T14:49:00Z")
You can start the other way around asking the question. What is it that needs to happen for a computer to get net access?
A typical set of issues needs resolving.
1. Who is the new computer? All network devices need an address. Since your computer is new to the network, something must allocate an address, and must communicate that address to the computer. This communication of address will typically occur over the network, so there is a chicken and egg issue to overcome.
2. How does the new computer know how to talk to the rest of the Internet? I needs to know how to find its way out of the network it has joined to the Internet, and it needs to know how to turn network names into addresses. The facilities on the network it has joined that do this are routers, and DNS servers. Your computer needs to know who these are. Someone has to tell it.
The typical answer to both the above questions is a service known as DHCP. The scenario is basically this:
Your computer shouts down the network, “Hi I’m \, what’s my IP address, and stuff I need to know?” and the DHCP server replies with an address, routing, and DNS server info. A typical WiFi network does this as a matter of course.
However a wired network is often designed much more securely. The DHCP server may be configured to only allocate a given IP address to a specific MAC address, and to ignore any other computer. (As noted above this isn’t terribly secure security, but is a speed hump.)
A very typical setup is to have the wired network quite secure, and the WiFi network quite separate, and a firewall between. WiFi connected computers might be allowed access to the wired side over a VPN, but are usually treated as untrusted, and no better than machines on the general Internet. As noted above, different companies have widely differing policies, but typically the idea of a random computer accessing the internal network is viewed badly. Many companies will require that the computer is managed by their IT group, sometimes even prohibiting the end user from having admin rights. And so it goes.