Hello,

I have been wrestling with creating a vlan to run experiments with and was hoping someone here would be able to give me some direction. I am using a system called GENI which allows users to reserve networked pc's from different colleges, businesses, etc. Users are able to design a topology and the geni system creates it then gives access to the resources for an allotted time.

Right now, myself and other users are only able to reserve linux machines and not actual switches or routers. What I am doing is reserving 5 machines in a star topology. By default each machine can ping every other machine but I want to separate them into vlans as per the requirements of the project. Currently using ssh to interact with each machine.

My question: Is it possible to set up a simple vlan between two or several machines using just linux boxes to create the vlan?

I have started using vconfig to tag the interfaces on the pc serving as the center connecting point for the other machines in my little network.

Any help or direction would be greatly appreciated.

Linux supports bridging and 802.1q VLAN tagging, so yes, you can create VLANs using only Linux. If the macines can ping one another, are they perhaps in different subnets? If so, you're using the hub node as a router, not a switch.

If none of the interfaces on the hub node are bridged, it really acts like a switch with 4 VLANs. You can bridge individual interfaces to make them members of the same VLAN (man brctl), and/or you can create 802.1q tag interfaces with vconfig and bridge them to another interface.

Okay that is good news. Sorry for being so vague. Here are the ifconfigs of the central hub node and one of the clients.

Router or hub node (linux machine)

eth0 Link encap:Ethernet HWaddr 00:02:b3:86:1d:f8
inet addr:155.98.36.142 Bcast:155.98.39.255 Mask:255.255.252.0
inet6 addr: fe80::202:b3ff:fe86:1df8/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:17481 errors:0 dropped:0 overruns:0 frame:0
TX packets:8221 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:24901063 (24.9 MB) TX bytes:629824 (629.8 KB)

eth1 Link encap:Ethernet HWaddr 00:02:b3:86:1d:f9
inet addr:10.10.1.1 Bcast:10.10.1.255 Mask:255.255.255.0
inet6 addr: fe80::202:b3ff:fe86:1df9/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:10 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:796 (796.0 B)

eth2 Link encap:Ethernet HWaddr 00:03:47:94:c2:91
inet addr:10.10.2.1 Bcast:10.10.2.255 Mask:255.255.255.0
inet6 addr: fe80::203:47ff:fe94:c291/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:9 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:978 (978.0 B)

eth3 Link encap:Ethernet HWaddr 00:03:47:73:a2:2d
inet addr:10.10.3.1 Bcast:10.10.3.255 Mask:255.255.255.0
inet6 addr: fe80::203:47ff:fe73:a22d/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:9 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:978 (978.0 B)

eth4 Link encap:Ethernet HWaddr 00:03:47:73:a2:2e
inet addr:10.10.4.1 Bcast:10.10.4.255 Mask:255.255.255.0
inet6 addr: fe80::203:47ff:fe73:a22e/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:9 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:726 (726.0 B)

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:83 errors:0 dropped:0 overruns:0 frame:0
TX packets:83 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:7627 (7.6 KB) TX bytes:7627 (7.6 KB)

Client machine

eth0 Link encap:Ethernet HWaddr 00:02:b3:65:cf:5e
inet addr:155.98.36.150 Bcast:155.98.39.255 Mask:255.255.252.0
inet6 addr: fe80::202:b3ff:fe65:cf5e/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:17749 errors:0 dropped:0 overruns:0 frame:0
TX packets:7947 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:25012028 (25.0 MB) TX bytes:620781 (620.7 KB)

eth1 Link encap:Ethernet HWaddr 00:02:b3:65:cf:5f
inet addr:10.10.1.2 Bcast:10.10.1.255 Mask:255.255.255.0
inet6 addr: fe80::202:b3ff:fe65:cf5f/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:11 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:1138 (1.1 KB)

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:83 errors:0 dropped:0 overruns:0 frame:0
TX packets:83 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:7635 (7.6 KB) TX bytes:7635 (7.6 KB)

It looks like each machine in my topology has a global ip according to eth0 but is also a part of the small 5 pc star topology I requested when reserving my resources. I think the machine is doing some sort of routing like you said because there are several different subnets configured. I have each of the 5 pc's on ubuntu 10.04.


here's the topology.
http://imageshack.us/photo/my-images/845/topology.png/


For the purposes of the project I am doing, I definitely want to create my own vlans. In the end, I hope to have just 2 vlans that can't access each other. Whenever I was using vconfig before I would tag an interface on the router machine like eth1 and add eth1.1. Then I would try creating a new network by giving it an address of 192.168.50.1 for the default gateway and netmask of 255.255.255.0.

Then I would go to a client machine that I would like to put on that vlan and give it an address of something like 192.168.50.2 and change the gateway to 192.168.50.1. I could never ping the gateway. Just having a hard time conceptualizing how this needs to be put together. Do i need to tag the vlan interface on the client machine as well?