Re: xen networking

[Greg Troxel <gdt%lexort.com@localhost>]

Iain Hibbert <plunky%ogmig.net@localhost> writes:

> I was having a separate difficulty on the dom0. You can't attach an IP 
> address to a bridge, so dhcpd won't touch it. Neither would dhcpcd and 
> dnsmasq complained about something. Linux bridge can have IP addresses 
> attached which would help with all that.

I think it's good that you can't put an address on a bridge.  Ethernet
switches do not have addresses (except for management).   So create a
tap0 and configure it with an address and put it in the bridge.

> dom0 just currently asks for an IP address on xvif1i1 which is the 

As I understand it, xvifN.M on the dom0 and domU-N xennetM are logically
on a separate virtual ethernet, one for each pair.  So you can put an
address on the xvif end.  In my setups, I didn't, and just put them in a
bridge with wm0, because I really wanted to just bridge the domUs to the
real ethernet, as if they were separate computers and plugged in.

I had forgotten about this, that you can  (I think) put an address on an
xvif.

>>   configure an address statically and try to ping the dhcp server
>
> Yeah I'm wondering about that. I'm guessing that my IP address will be 
> fixed, so I could perhaps just set it up as static in the domU-router.

If you can get a second IP address for the domU router, that's a
reasonable approach.  Then you can just bridge the xvifZ.0 for the
domU-router to wm0.   But your provider LAN has to be ok with that behavior.

>>   also look at arp with tcpdump
>
> looking for what, the MAC address of domU-router xennet0 ?  I can see some 
> other who-has stuff going on out there in general but nothing specific to 
> my domU-router requests

yes, basically the arp traffic done by the domU.  But I realized that
the domU is doing dhcp, not IP yet, so there may not be any.   My real
point was to get the domU to have an address that works, before you
worry about NAT.