[lug] need routing help with kvm

[Michael J. Hammel]

I'm trying to setup routing for a vm on a host that is on a subnet that
is on our corp net.  I want the VM to be able to reach the corp net.
The VM is a KVM guest running CentOS.  The VM host is also running
CentOS.

The default NAT on the vm (via virt-manager) sets up the VMs subnet as
192.168.122.x.  This VM guest is 192.168.122.26.  The vm host is
192.168.2.129 and 192.168.122.1.  The .2 gateway to the .1 network is
192.168.2.65.  A host on the corp net is 192.168.1.63.  

The VM can ping .122 hosts (including the vm host).  It can also ping
anything on the .2 network (of which the vm host is a member).  It
cannot reach anything on the .1 network (or anything in the outside
world, which is on the other side of the .1 network, but I just need
access to .1 for now).

The VM host can access the VM guests, the .2 network and hosts on .1.

The VM guest's route table is:
192.168.122.0  *             255.255.255.0  U   1  0  0 eth1
default        192.168.122.1 0.0.0.0        UG  0  0  0 eth1

The VM host routes are:
192.168.100.0 *            255.255.255.0 U  0    0 0 virbr2 
192.168.2.0   *            255.255.255.0 U  0    0 0 br0  
192.168.109.0 *            255.255.255.0 U  0    0 0 virbr1 
192.168.122.0 *            255.255.255.0 U  0    0 0 virbr0 
link-local    *            255.255.0.0   U  1003 0 0 br0  
default       169.254.0.0  0.0.0.0       UG 0    0 0 br0  
default       192.168.2.65 0.0.0.0       UG 0    0 0 br0

br0 is a bridge to the physical interface on the vm host.  virbr? are
bridges created via the virt-manager interface.

I've tried all kinds of route changes to the VM and the vm host.  It
seems the vm host will not route through the 2.65 gateway for the VM
guest.  I'm not certain at this point if the routing is a problem with
the route tables in the VM guest and/or VM host or a configuration
problem with libvirt's network configuration for default.xml.  I've
tried creating new networks via virt-manager but that didn't do much
different than what was in default.xml.

Any pointers?
-- 
Michael J. Hammel                                    Principal Software Engineer
mjhammel at graphics-muse.org                           http://graphics-muse.org
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                Everything should be made as simple as possible.  
                    But not simpler.  --  Albert Einstein.