Pietro Paolini pulsarpietro at
Thu May 30 15:21:27 UTC 2013

On May 30, 2013, at 2:29 PM, Joe <fbsd8 at> wrote:

> Pietro Paolini wrote:
>> Hello all,
>> I am a new bye on the FreeBSD and I am looking at the VIMAGE features experiencing some problems.
>> I added the options :
>> if_bridge
>> and I removed
>> then I recompiled my kernel and install it.
>> After that, following this tutorial I tried the "Exercise 2" which consist on the following commands:
>> vimage -c n1
>> vimage -c n2
>> ngctl mkpeer efface ether ether
>> ngctl mkpeer efface ether ether
>> ngctl mkpeer em0: bridge lower link0
>> ngctl name em0:lower bridge0
>> ngctl connect em0: bridge0: upper link1
>> ngctl connect ngeth0: bridge0: ether link2
>> ngctl connect ngeth1: bridge0: ether link3
>> vimage -i n1 ngeth0 e0
>> But my virtual interface on the n1 vimage does not receive any packet from the external network while I can see the packet go out from it.
>> For instance using DHCP, e0 on n1 sends DHCP packets but it does not receive the answers (which are send, I verified it from wireshark), in adding
>> the ARP request for his IP address (if I try to add it statically) are not received then it can not answer.
>> At the end of the line the question is: how can I make this "virtual network" and the external real network be able to communicate ?
>> Thanks in advance.
>> Pietro.
> 1. That link is from 2007. So very much has changed since then.
> There are more current links on the internet about this subject. Most are for 8.X releases.
> 2. If your running 8.2-RELEASE or 9.1-RELEASE all you need to add is "options vimage" statement to your kernel source and recompile.
> 3. There are 2 networking methods available for creating vnet/vimage jail networks, if_bridge/epair and netgraph. The if_bridge/epair method is far simpler to config and use then the netgraph method.
> 4. There are 2 methods of jail setup, the rc.d method where your jail definition parameters go into the hosts rc.conf and the jail(8) method where you can place each jails definition parameter in separate files.
> 5. There are two very important show stopper PRs on vimage,
> 164763 memory leak and 149050 the rc.d keyword "nojail" problem.
> Vimage is a very long way from prime time usage, thats why it's labeled as highly experimental. Host system freezes and page faults are common.
> 6. When it comes to running a firewall in a vnet/vimage jail your limited to IPFW and it has limitations. Dummynet and in kernel NAT cause system freezes. IPFILTER causes page fault at boot time. PF will run on the host but not run in the vnet/vimage jail. Here are a bunch of PRs on vimage firewall problems, 143621, 176092, 161094, 176992, 143808, 148155, 165252, 178480, 178482
> Check out these links
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Thanks so much, really interesting and good links but I can't again accomplish my task - I followed as a base tutorial - 

I would like simulate more client for my PC using this technology, and that's my topology:

1 - Two epairs created 
2 - Two jail created
3 - Assign one intf for jail
4 - Add the real interface to a bridge where I put all the interfaces



em0 --> REAL

Where {0,1}a is the first pair and {0,1}b is the second and em0 is my real interface (it has an IP address), then I got to the problem, I tried 
to :

jexec 2 dhclient epair1b  

And I can see the DHCP packet with the correct MAC address going out, the server reply (I have a sniffer pc) but the transaction does not end successfully, what is really strange is that if I attach tcpdump on em0 I can NOT see the answer server sends while when I try

dhclient em0 

I can see the packet going in and out and the DHCP transaction finish successfully. Do you have any idea about how can I accomplish my 
target ? Maybe I am using the wrong technology ?

I would not surprised if I make a error on my configuration but what really interest me is if I CAN do that using jail.

Thanks a lot, and in advance ! :-)


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