Re: [Libvir] Patch for routed virtual networks

søn, 09 03 2008 kl. 21:09 +0000, skrev Daniel P. Berrange: > On Sat, Mar 08, 2008 at 04:33:32PM +0100, Mads Chr. Olesen wrote: > > I have added a <route dev="ethX" /> stanza (dev is optional), completely > > equivalent to the <forward /> stanza. > > This is still forwarding of traffic, so I think we should just use the > existing <forward/> element and have an extra attribute to indiciate > the type of forwarding, eg > > <forward/> (defaults to mode="nat" for compat) > <forward mode="nat"/> > <forward mode="route"/> > <forward mode="nat" dev="ethX"/> > <forward mode="route" dev="ethX"/> Sure, makes sense - an updated patch is attached. > I'm a little unclear on how this actually works. You add iptables rules to > allow traffic in/out, but you're not adding any routing table entries, nor > turning on proxy_arp, so I don't see how this will actually work in practice. > > Are you assuming the admin has already added suitable routing rules & turned > on proxy arp ? Well, in my case (dedicated server, hetzner.de) this is all that is needed. My physical interface has IP 85.10.XXX.XXX, and then I have a secondary IP range which gets routed at that interface, IP range 78.47.YYY.YYY/30. I then setup my virtual interface with an IP in that range, by setting <ip address="78.47.YYY.YYY" netmask="255.255.255.248" /> Thus, to get packets routed at the virtual machines, it just needs to be allowed by iptables, and /proc/sys/net/ipv4/ip_forward needs to be set to 1. Other setups obviously might need more work.