[Bridge] pinging other side (normal bridge ok, anonymous bridge not ok)

[Alexis Huxley]

> Is veth1 up? (Maybe you need "ifconfig veth1 up".) You shouldn't need
> the iptables line unless you have other iptables stuff that might
> potentially block it. And there are some emails on the web referring
> to issues with iptables conntrack and veth.

Well, as kind of predicted by everybody, I eventually switched to putting
an IP address on br0. The reason was that when I configured tap0/eth0
in the VM then masquerading did not work correctly; the first ping from
inside the VM to the internet worked, but then immediately it stopped.
I did some googling and it seemed not an uncommon problem, but a quick
test of putting an IP on br0 immediately solved the problem. Thanks
again for the all the very good and speedy advice I was given!

Alexis