Re: [Qemu-devel] Connecting vde and LAN

[Henrik Nordstrom]

On Sun, 10 Jul 2005, Oliver Gerlich wrote:

> what is the best solution to connect the vde "switch" to my real LAN so
> that Qemu guests get IPs from my LAN-wide DHCP server?

bridgeing of your ethernet interface and the TAP interface connecting to 
vde is undoubtly the best if you want to provide full access to the LAN.

> So far I've experimented with bridging tap0 and eth0 so that the Qemu
> guests are transparently on my LAN and get IPs from the LAN-wide DHCP
> server. But this has the drawback that my host network interface is now
> br0 instead of eth0 (that causes confusion at least for samba).

Fix the Samba problem?

Why does this cause problems for Samba? I run my qemu stations like this 
all the time, but not using Samba..

> Also I tried to set up IP forwarding between tap0 and eth0, but then the
> Qemu guests aren't transparently on my LAN (and don't get the correct
> config from the DHCP server).

Correct.

DHCP is Ethernet broadcast based, not IP.

You could in theory run a DHCP proxy agent on your tap0 interface, and 
have the DHCP server configured with a suitable scope. But this does not 
give you addresses from your LAN.

You could also run a local DHCP server on tap0, configured with the 
address scope you have set up proxy-arp for. But these addresses better be 
statically assigned to you, never handed out by the LAN DHCP server to 
anyone else in the LAN. But this doesn't provide true LAN access, only 
routed acces to the LAN (no broadcasts).

Regards
Henrik