On 06/06/2016 08:48 PM, Rainer Weikusat wrote:
Simon Walter <si...@gikaku.com> writes:
On 06/05/2016 12:16 AM, Rainer Weikusat wrote:
Simon Walter <si...@gikaku.com> writes:

[...]

I am adding containers (LXC) and
virtual network to the box, I think I will add an tap and bridge
interface to an /etc/network/interface.d/ file. If I use something
like:

auto br0
iface br0 inet static
      pre-up ip tuntap add dev tap0 mode tap
      pre-up ip link set tap0 up
      post-down ip link set tap0 down
      post-down ip tuntap del dev tap0 mode tap
      bridge_ports tap0
      address 10.1.1.1
      netmask 255.255.255.0
      broadcast 10.1.1.255

And make sure there is the source /etc/network/interface.d/* line in
the interfaces file. Then route with iptables between the a physical
NIC (eth0 for example) and the virtual NIC (tap0) and have all the
containers connected to br0.

Are there any glaring problems with this setup?
This will create a bridge with one virtual network interface bridged to
a character device an application could use to talk 'ethernet' to the
network stack. That's certainly not inherently related to/ useful for
anything-lxc.

I will route the packets to the physical device using iptables,
thereby creating a firewalled private network. I have only tried it
out and not done much research and testing on whether this is actually
secure or not.
You don't need the tap port for that, the bridge will happily work
without any ports statically assigned to it.

And will I be able to set up iptables with just the bridge? I was thinking of using shorewall. I've never used it before, but it seems like it's configuration is easy to maintain. Therein lies my concern. There are zones with interfaces for each zone. For some reason I thought a bridge needs to at least have one interface that it is bridging for it to be up. Can I bring a bridge up and do iptables stuff with it having no interfaces that it bridges?


The machines I'm dealing with use a bridge as 'main interface' a
principally arbitrary number of (lxc) containers connect to via veth
with one physical interface also assigned to the bridge to provide
actual connectivity. It's also possible to do packet filtering between
bridge ports if that's considered to be desirable/ useful.

I want to filter packets between physical NIC (WAN, eth0) and a virtual internal network (LAN, br0/tap0???). I am basically creating an isolated virtual network with virtual machines all inside one machine. Each container will have just enough software to carry out it's place in the network. Thereby isolating everything as much as possible, allowing for independent updates, modifications, hotswaps, etc.

  'Introduction
site'

http://ebtables.netfilter.org/

One of the advantages of ip(route) over the older, BSD-style tools is
that they can be used to assign an arbitrary number of protocol
addresses to a single interface without employing 'interface aliases'.

Good to know. Thank you!

Simon
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