[fedora-virt] F18 Host Only one Guest (currently) cannot connect to host, ping, web anything

[Laine Stump]

On 03/24/2013 08:29 AM, Frank Murphy wrote:
> Installed my first guest F16 Xfce 32bit (EOL, test)
>
> No virt-preview installed standard repos only.
>
> Virt-Manager in use.
>
> The default "virt-network is there"
> have tried it both NAT and routed,
> deleted it, re-installed no joy.
>
> Both eth0, eth1 show up in "Network Interfaces" tab
> with their DHCP ipv4 info (ipv6 disabled on host by choice)
>
>  ~]# ifconfig
> eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
>         inet 192.168.0.6  netmask 255.255.255.0  broadcast
>  192.168.0.255 ether 90:2b:34:98:cb:28  txqueuelen 1000  (Ethernet)
>         RX packets 60  bytes 9351 (9.1 KiB)
>         RX errors 0  dropped 0  overruns 0  frame 0
>         TX packets 51  bytes 5856 (5.7 KiB)
>         TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
>
> eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
>         inet 192.168.0.193  netmask 255.255.255.0  broadcast
> 192.168.0.255 ether a0:f3:c1:00:56:bb  txqueuelen 1000  (Ethernet)
>         RX packets 138  bytes 75894 (74.1 KiB)
>         RX errors 0  dropped 0  overruns 0  frame 0
>         TX packets 165  bytes 15167 (14.8 KiB)
>         TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
>
>
> virbr0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
>         inet 192.168.1.1  netmask 255.255.255.0  broadcast
> 192.168.1.255 ether 52:54:00:c6:4c:07  txqueuelen 0  (Ethernet)
>         RX packets 0  bytes 0 (0.0 B)
>         RX errors 0  dropped 0  overruns 0  frame 0
>         TX packets 4  bytes 854 (854.0 B)
>         TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
>
>
>
> cat default.xml <snipped>
> <network>
>   <name>default</name>
>   <uuid>e5216e09-7d6d-7999-0327-67ca7ecc5c60</uuid>
>   <forward dev='eth1' mode='route'>
>     <interface dev='eth1'/>
>   </forward>

1) setting forward dev='eth1' very likely isn't doing what you think
it's doing. Setting the forward dev does not change any routing
decisions for the packets, it merely causes packets that would have been
forwarded out any other interface to instead be rejected/dropped.

2) Add that to the fact that your eth0 and eth1 both have IP addresses
on the same subnet, and you're setup for almost certain failure (since
it's unclear which interface would be used for any given packet)

3) If your network has forward mode='route', then the machines on the
network beyond the host must have a route for 192.168.1.0/24 that points
back at your virt host (192.168.0.6 or 192.168.0.193, pick one).

My recommendation:


1) since eth1 appears to be connected to the same subnet as eth0, just
disable it (if you *really* need the extra bandwidth, bond the two
interfaces together).

2) remove the "dev='eth1'" and "<interface dev='eth1'/>" from your
network definition.

3) unless a) you need to support incoming connections to your guests
from the outside *and* b) the rest of the network has a route for
192.168.1.0/24 pointing back at the host, change the forward mode of the
network from 'route' to 'nat'.


>   <bridge name='virbr0' stp='on' delay='0' />
>   <mac address='52:54:00:C6:4C:07'/>
>   <ip address='192.168.1.1' netmask='255.255.255.0'>
>     <dhcp>
>       <range start='192.168.1.10' end='192.168.1.25' />
>     </dhcp>
>   </ip>
> </network>
>
>
> Booting F16-DVD in rescue mode on guest still no joy.
>