Hello, I might be the first to encounter this issue, so I think it is worth posting...

I am trying to set up a configuration in which a DomU and Dom0 are on their own subnet, and DomU accesses the real network through Dom0's NAT.

These are the steps that I take (note, these steps worked fine in "testing" and "stable" branches):

I first set up a bridge with a private IP:

brctl addbr mybr0 ip addr add 192.168.0.1/24 dev mybr0 ip link set mybr0 up

These are my network scripts in the xend config file:

(network-script network-route) (vif-script vif-bridge) (vif-bridge mybr0)

I start a DomU with an IP of 192.168.0.101, and I am able to ping Dom0 (192.186.0.1).

I enable IP forwarding, and I set up NAT:

sysctl -w net.ipv4.ip_forward=1 # (if not allready done by xend) iptables -t nat -A POSTROUTING -j MASQUERADE \ -o eth0 -s 192.168.0.1/24

I am able to ping the outside world by IP, but name resolution, or any other TCP/IP traffic does not work. The very strange part is that tcpdump seems to show packets arriving at their destination on the outside world hosts. but besides the ACKs, the outside hosts do not respond. I am not a networking expert, so I am sorry if my diagnoses is not full.

Here is a bit more info (on Dom0): # iptables -t nat -L Chain PREROUTING (policy ACCEPT) target prot opt source destination

Chain POSTROUTING (policy ACCEPT) target prot opt source destination MASQUERADE all -- 192.168.0.0/24 anywhere

Chain OUTPUT (policy ACCEPT) target prot opt source destination

# ifconfig eth0 Link encap:Ethernet HWaddr 00:0F:1F:8C:17:D6 inet addr: 10.0.20.10 Bcast:10.0.255.255 Mask:255.255.0.0 UP BROADCAST NOTRAILERS RUNNING MULTICAST MTU:1500 Metric:1 RX packets:30868 errors:0 dropped:0 overruns:0 frame:0 TX packets:1121 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:8172500 (7.7 Mb) TX bytes:158965 (155.2 Kb) Base address:0xdf40 Memory:fcfe0000-fd000000

lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:5 errors:0 dropped:0 overruns:0 frame:0 TX packets:5 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:288 (288.0 b) TX bytes:288 (288.0 b)

mybr0 Link encap:Ethernet HWaddr FE:FF:FF:FF:FF:FF inet addr:192.168.0.1 Bcast:0.0.0.0 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:12 errors:0 dropped:0 overruns:0 frame:0 TX packets:13 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:834 (834.0 b) TX bytes:938 (938.0 b)

vif1.0 Link encap:Ethernet HWaddr FE:FF:FF:FF:FF:FF UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:13 errors:0 dropped:0 overruns:0 frame:0 TX packets:10 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:1044 (1.0 Kb) TX bytes:812 (812.0 b)

# brctl show bridge name bridge id STP enabled interfaces mybr0 8000.feffffffffff no vif1.0