Qemu network question

[Mario Lobo]

Hi:

Please use a fixed font to see the diagram bellow:


       FBSD HOST(7.1-PRERELEASE)
      +-----------------+
      |    10.10.10.1   | 
 LAN -+----- re0        | 
      |                 | 
      |    +-----+      |
  +---+----+tap0 |      |  
  |  ++----+tap1 |      | 
  |  ||    +-----+      |  
  |  ||    bridge0      |  (if_bridge)
  |  || 192.168.100.254 |  
  |  |+-----------------+
  |  |
  |  |      QEMU GUEST 1 (linux Fedora core 5)
  |  |   +-----------------+
  |  |   |                 |
  |  +---+---- eth0        | 
  |      | 192.168.100.1   | 
  |      |                 | 
  |      +-----------------+ 
  |         QEMU GUEST 2  (windows XP)
  |      +-----------------+
  |      |                 |
  +------+--- realtek      | 
         | 192.168.100.2   | 
         |                 | 
         +-----------------+ 

It's working like a charm ! 

I turned my FBSD desktop into a router/gateway, put pf to nat everything and 
set up an independent smb server on the host. Pings travel on any direction!. 
The guests have access to ALL the host's files and vice versa, BOTH guests 
have internet access and best of all, I can access the linux guest through an 
ssh shell and the windows guest through vncviewer, and, of course, the 2 
guests see each other ! Imagine how happy I am !

I tried this without turning my desktop into a gateway. The guests had 
internet access but the host was invisible to them and I got tired of trying 
to make qemu's -smb option work, so I adapted this "a-bit radical" approach I 
saw on a how-to for Sun OS I found on the net.

I'm really impressed with qemu performance !. I´ve compiled kernels, built 
RPMs and the reduction in performance from doing these things in a separate 
machine is really endurable.

My question is: If I don't put re0 into promiscous mode, all of this falls 
apart ! The network goes totally down for the host<->guests, but the host 
retains its internet conectivity. I discovered that by chance! I was trying 
to find out what was happening with conectivity so I tried pinging the host 
from the linux guest. As soon as I started tcpdump on the host, the pings 
went through so I found out what I needed from there.

Is this normal or is there something wrong with my NIC? setup?

Thanks,
-- 
Mario Lobo
http://www.mallavoodoo.com.br
FreeBSD since version 2.2.8 [not Pro-Audio.... YET!!] (99,7% winedows FREE)