[kwlug-disc] Virtual nic flowing out regular nic.

[B.S.]

Assume regular computer / network connectivity. It happily connects / communicates out eth0.

I am trying to bind an app to a different interface so it gets it's own isolated ip address (not on the regular lan). It will not bind to an alias. (ifconfig eth0:0 ... will not work) Call it fakeeth0 for our purposes here.

I expect fakeeth0 go out eth0 for all its connectivity, seamlessly.

I expect an arp 'who has' to find it. i.e. Layer 2 is bridging. (Even if it doesn't, I can put routes in so things can find their way back.)



- this is no different than connecting a 2nd computer to the same switch with a different IP address, and able to happily connect to other computers on the same (different) net. (This is different nets on the same physical backbone.) Which is to say, I see no point to a vlan. (ifconfig eth0.1 ... seems adding unnecessary complexity. Security is not an issue.)

e.g. Physical:

Comp 1: 192.168.0.1/24 ('Lan' 1, == subnet 1)
Comp 2: 192.168.1.1/24 ('Lan' 2, == subnet 2)
Comp 3: 192.168.0.2/24 ('Lan' 1, == subnet 1)
Comp 4: 192.168.1.2/24 ('Lan' 2, == subnet 2)
- all on the same switch.

Comp 1 & 3 ('Lan' 1 == subnet 1) and 2 & 4 ('Lan' 2 == subnet 2 ) will happily talk between themselves. (I can put a subnet 2 address on a subnet 1 computer, enable forwarding, and they all will then talk to each other).


Now ... virtualize it.

[Comp 1: fakeeth0 -> eth0] -> [Comp 2: == eth0's gateway] -> [internet]

I have tried various interfaces: tap0, macvlan0, macvtap0, br0, and I'm not getting the expected layer 2 bridging and forwarding out the physical eth0.

What am I missing?

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Ultimate goal: {vbox1 - fakeeth0 (connected to nothing)[allowing the app to bind to it], eth0 bridged to host} -> the world happily connected as usual.

Ultimate goal+: {vbox1 - fakeeth0 (connected to nothing)[allowing the app to bind to it], eth0 hostonly to host} -> the world happily connected as usual.
(This, however, means adding a default route on vbox1, and a route back to fakeeth0 via host, specified on the net. This is OK. But first things first.)


At the moment, even using physical machines, with one having a fakeeth0, fakeeth0 is not automagically going out eth0. What am I missing?

<arrgghh!!>