Best practices with network settings for virtualization

Julian Elischer julian at
Tue May 13 15:42:08 UTC 2014

On 5/13/14, 6:54 AM, Miroslav Lachman wrote:
> I originaly posted this to virtualization@ list week ago. I didn't 
> recieved any answer, so maybe this list is better for questions like 
> the following.
> I would like to ask some really experienced person - what is the 
> best way to run virtual guests connected to network with public IPs?
> I think many people run unsecure setup with guests with simple 
> bridged network.
> I know there are many options with tun, bridge, epair, VDE, Open 
> vSwitch etc., my main concern is the setup of network where each 
> guest can use only predefined MAC and predefined IP(s). If some 
> malicious user or malware in guest OS tried to change MAC od IP, I 
> would like to disallow that or do not allow any offending traffic to 
> reach outside network or any other guest running on the same machine.
> Guests can be VirtualBox, Bhyve or anything else.
Assuming you mean virtualization like bhyve and not virtualization 
like jails, ad that you can use private addresses for the VMs, you can 
still run each virtual machine inside a VNET jail, then using 
something like epair you can connect the jails  to a central 'router' 
jail  that runs ipfw and enforces what each jail sends out.

If you want actual routable addresses on each jail (so that the jail 
sees the outside workd directly it's a bit more difficult because you 
can't act as a 'router' in the middle. Maybe others have more ideas.

If you need to bridge a bunch of virtual machines so that they have 
addressable interfaces. you can run bhyve or VB inside a vnet jail as 
above but each jail would need to do its own enforcing by having its 
own ipfw, listenning on the virtual interface that is attaching to the 
bridge. I have not done htis but I'm sure it can be done. you'll need 
to experiment.
just remember that each  VNET jail can have it's own firewall and it's 
own interfaces. real or virtual.

> I really appreciate any help or ideas.
> -- 
> Miroslav Lachman
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