Hi Nick,
 
Thanks for your very helpful email.
 
What I want to set up, is a 3 interface system: WAN, LAN and 
DMZ.
 
So far, the lauout I'm thinking is similar to this:
 
In a nutshell, I will probably create a firewall in a DomU, and 
delegate a PCI physical NIC to it (which will be used for the firewall's WAN 
interfae). Then create 2 "bridges" (one for "LAN" interface, and one for 
"DMZ" interface) and assign a vif from each bridge to the firewall DomU. Neither 
bridges will have a physical NIC attached to it. Of course, there will be other 
DomUs connected to the respective bridge. The 2nd physical NIC of the server 
will be delegated to a DomU machine in the "LAN" subnet. This will be an LTSP 
Terminal Server, and will be connected to a physical switch for all my thin 
clients to connect to.
 
I intend to use pfsense (Which is BSD based, which I think works 
with HVM mode) in the DomU, instead of shorewall (as described in that 
link).
 
For the actual bridges, I will probably follow the following link 
so make it more "Layer 3 switch like":
 
I will probably need a 3rd NIC to access as a management interface. 
I really do need some help secureing the Dom0.
 
Think this is safe? I really do need it to be very secure, due to 
PCI (credit card details) compliance
 
Thanks
 
Jonny
 
 
> Hi Nick,
>
> Thanks for the 
email.
>
> I currently use the free version of VMWare ESXi, and I 
can make my "own
> world" with it. You say I can do this with XCP, however 
is it just for
> testing purposes? Is it insecure for production 
purposes?
>
Sorry to be unclear about that - my pointing out the 
usefulness for testing purposes, I was not saying that it's insecure or unstable 
for production use.  It just seems to me that about the only time you want 
your virtual machines on an isolated network is when you're doing some sort of 
Test/Dev environment - production machines are most useful when they're 
connected with the rest of the world.  I can see some scenarios where you'd 
use an internal network, though, to connect some production machines, in 
addition to their external network devices.  Anyway, the point is that, 
yes, the ability to create a bridge in XenServer/XCP/Xen is stable, secure, and 
production-ready.  Just create a bridge without an external network 
device!
-Nick
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