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I have two turtle bots with an Intel NUC on it, and a Linux PC.
They all have to communicate bidirectionally with each other on a network.
An obvious choice would be SSH, but the university blocks all communication between computers on the network.
As a temporary solution, we are planning to use Ethernet cables for communication.
So there are two cables coming from the NUCs that have to communicate to the PC, which should be connected to the internet.

Any ideas on how to set this up?

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  • I am not a network engineer or a big Linux user, but if your Linux PC has 3 NICs in it, you should be able to run crossover cables from the NUCs to the Linux box, and then a regular cable from it to the internet. The Linux box will then basically be a router. You'll need to configure it to do internet sharing, which I'm afraid I am ignorant of on Linux (or any PC now, since it's been >10 years since I last had to do that). – techturtle Oct 25 '17 at 14:24
  • why not get 3 cheap wireless USB NICs and use an ad hoc network? – Keltari Oct 25 '17 at 14:29
  • @Keltari The university doesn't allow us to set up our own network, because it interferes with their network – user7845839 Oct 25 '17 at 14:35
  • @techturtle the PC has only one NIC – user7845839 Oct 25 '17 at 14:39
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    Either get more NICs for the Linux PC, or even better, just get a cheap hub/switch and connect all the machines to that. That would even save you the effort of configuring the "router" functions of the Linux PC. – techturtle Oct 25 '17 at 14:43
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Get an inexpensive wireless router (around $20). Keep the Linux PC connected to the university's network and internet via ethernet. Connect the Linux PC to the router using wi-fi, and the NUCs either with wi-fi or ethernet. Do not connect the WAN/Internet port of the router.

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Most likely the router will come out of box using a 192.168.1.0 subnet, and the university will be using a different subnet, and nothing will need to be changed. However, you should check this, and if they're the same, change the router to something else, for example 10.7.7.0 (or anything starting with 10).

P.S. To clarify, the use of the word "wi-fi" here is not the university's wi-fi. You will be creating your own local wi-fi network that isn't part of the university. This is the same idea as creating a "mobile hotspot" with a cell phone.

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  • This looks like a fair solution. But is it allowed if the university doesn't allow a router in their network? – user7845839 Oct 26 '17 at 10:16
  • @user7845839 That's the whole point of this setup. The router doesn't touch the university's network. – Jason Oct 26 '17 at 15:27
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I suggest getting a small office/home office router with which to connect all your devices together. The router's WAN port would then be connected to the University network.

Check with University's guidelines on this matter: installing a WiFi access point may be forbidden, so that feature might have to be disabled on the router, if applicable. Otherwise, there is little or no additional configuration required, except possibly assigning specific IP addresses to each devices' MAC address in the router's DHCP facility.

Some benefits to this approach include having a local private network on which all ports and traffic will be open and unrestricted between the individual hosts, automatic DHCP configuration will place all hosts connected to the router in the same network by default, each host can access the Internet if required through the router, and network traffic generated between the hosts behind the router does not interfere with the University network.

This design is also highly portable: It can be taken to another office, another building, another campus, home, or anywhere else and still work the same, regardless of what network to which the router's WAN port connects, if any.

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  • The reality here is if they won't allow a router in the network, you can't connect connect the NUCs to the Linux machine anyway, because it would then become a router itself, functionally no different (assuming the NUCs would have a route to the university network). Otherwise you could get a cheap nic card and a switch, assign the nic and NUCs static IPs in a unique subnet and it should work. – acejavelin Oct 25 '17 at 16:37
  • I believe it's a general policy to not allow non-authorized WiFi access points onto a campus/corporate netowrk. – Nevin Williams Oct 25 '17 at 17:01
  • Checking about acceptable use prior to making a network never got anyone in trouble. – Nevin Williams Oct 25 '17 at 17:02
  • Putting several devices on a switched netork connected to a LAN and assigning them IPs willy-nilly is a great way to have your network port shut off without notice. – Nevin Williams Oct 25 '17 at 17:07
  • @NevinWilliams The university doesn't allow a router in the network. Why do I need both a NIC card and a switch? – user7845839 Oct 26 '17 at 10:15
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This really depends on your university. Since you're probably in the CIS department your university really should be providing you with an isolated network so that the computers in that network can talk. If not your network administrator is incompetent. If you haven't asked.. ask. They'll probably do it for you.

Do not put computers on your network behind another NAT firewall (the wan port with its default settings) as this provides a very false sense of security even assuming its allowed. Further connecting your systems up via wifi circumvents what ever policy your university has about wifi enabled devices.

You could connect the computers via Ethernet on a secondary NIC for each computer and keep them on the same subnet which maintains network isolation. Similar things are possible with IPv6 without using multiple NICs.

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