At beginnig, when I play with Xen, I was on a small local lan, and by this way, we were allocated a range of ip. So, this wasn't difficult to configure a xen machine, and get network working out of the box with dhcp.
I simply edit the file :
and enable these two line :
At home, a different configuration is needed as my provider don't give as many IP as I want. The solution was to used a nat, and Xen provide this out of the box, you only need to comment these two lines :
and uncomment these two line :
At this moment, I still cannot resolv any host name, but I can ping the internet, I probably forget something, and put how to do that as soon as I find a solution.