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I'm researching a project. If lets say a lab has 20 PC, 1 tutor PC and the rest is 19 student pc, and in my project all the network traffic from student pc should go through the tutor pc before reaching its destination thus, the tutor PC must have two ethernet cards: card A for communication with student PCs and card B for communication with the gateway.

In detail, card B have IP address 10.21.2.* and gateway IP; card A is configured to be a gateway for student PCs with another IP address range (e.g., 192.168.0.*). And configure the tutor PC to share internet connection via card B.

Beside using this approach, is there any other method to configure the tutor pc as the gateway for the student pc's without adding extra Ethernet carD? please advice.


locked by HopelessN00b Feb 17 '15 at 16:50

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closed as off-topic by HopelessN00b Feb 17 '15 at 16:50

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stuck on your homework? – t1nt1n Apr 16 '12 at 16:51

Easier way - get software meant for managing a lab. There are programs that control what the clients see (tutor PC display, their own display), blanking the screen, cutting off internet browsing, monitoring what's on the display, etc.


vLANs. One for each network, and trunked to the Tutor's NIC.

do you mind to explain more what do u mean VLAN here? – houstonCYap Apr 16 '12 at 16:08
"other method to configure the tutor pc as the gateway for the student pc's without adding extra Ethernet carD" <-- vLANs allow a single NIC to be connected to multiple Virtual LANs. Seriously, you need to find a competent network admin and hire him to help you. This site is meant to help SysAdmins solve problems. We are not here to tell you how we do our jobs, that amount of information would fill whole books anyway. – Chris S Apr 16 '12 at 16:11
See proposed link. VLANs need to be supported by your active network equipment (e.g. ethernet switch(es) used to connect all lab pc's). In brief, VLAN technology allows you to organize several logical connections (to different networks) over single physical connection. In this case, usually, for each virtual LAN your computer would have separate virtual network interface although only one physical NIC. – Vadym S. Khondar Apr 16 '12 at 16:15

My other answer was more in line with what you had previously posted as a question and I believe it was closed; but really, the question is, what are you trying to achieve? Are you monitoring traffic? Are you cutting off Internet access while talking? Are you trying to proxy web access? Because really you're just asking for all the traffic in the lab to be bottlenecked at a single computer before going out, with no end goal to achieve other than bottlenecking them.

If you want to keep them paying attention, there's the software I mentioned, or if there's a switch for that lab you can pull the uplink cable (which your sysadmins will most likely frown on.)

Or you can set up a proxy system that forwards traffic, like a Squid web proxy. There are turnkey Linux/BSD distros that act as gateway/routers that can then forward traffic on for you (although you'd want this to be uplinked from the single switch if you want to make sure the traffic doesn't bypass the proxy/filter, otherwise all the machines in that lab will need their gateway specified as that router machine and they could conceivably bypass your configured bottleneck.

Anything you do to "segment" off this network this way, by routing it through a special PC, is going to add what is probably an unnecessary layer of complexity for network management, and if you're not the admin for this network doing this will not endear you to them. If you have a direct concern...keeping users from web browsing during a class, speeding up access to sites, may wish to state your actual end goal rather than coming up with a solution of sorts in your mind already and asking how to achieve your solution. Putting in barriers that could muck up DHCP or other network management within the context of the higher-up network admins taking care of all the systems will ask for trouble. Not to mention someone may ask why, when the teacher computer is taken out for repair or has a disk failure, the entire lab suddenly became useless...

Are you demonstrating MITM attacks? – ewanm89 Apr 16 '12 at 17:24

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