Cannot connect VM to the internet

Hello,

I'm a beginner with proxmox (and not an very experienced in Linux). I bought a Proliant G5 in order to do tests at home and was surprised how easy it is to create/backup VM's and to access/use them from/within the intranet.

I created a OpenVZ Container (Debian 7) with Network -> Bridged Mode -> vmbr0. And then assigned an IP by choosing Network -> Add -> IP Address (venet) -> 101.101.101.199.
Finally the /etc/network/interfaces of the host is

auto lo
iface lo inet loopback
iface eth0 inet manual
iface eth1 inet manual
auto vmbr0
iface vmbr0 inet static
address 101.101.101.32
netmask 255.255.255.0
gateway 101.101.101.200
bridge_ports eth0
bridge_stp off
bridge_fd 0

and the /etc/network/interfaces of the VM is

auto lo
iface lo inet loopback
auto venet0
iface venet0 inet manual
up ifconfig venet0 up
up ifconfig venet0 127.0.0.2
up route add default dev venet0
down route del default dev venet0
down ifconfig venet0 down
iface venet0 inet6 manual
up route -A inet6 add default dev venet0
down route -A inet6 del default dev venet0
auto venet0:0
iface venet0:0 inet static
address 101.101.101.199
netmask 255.255.255.255

I can access the host with 101.101.101.32 and the VM via 101.101.101.199. OK!

Then I ordered a dedicated server and and set up the same configuration but
A.B.C.D instead of 101.101.101.32
w.x.y.z instead of 101.101.101.199
A.B.C.1 instead of 101.101.101.200

The problem is that I can ping w.x.y.z from the host and A.B.C.D from the VM, but I cannot access the VM from the internet, and I cannot access the internet from inside the VM.
Unfortunately, I don't understand the posts that I have found in the Web about that problem and its solution. The problem seems to be that w.x.y.z is not in the subnet of the gateway A.B.C.1, but the hints given about that topic do not work (at least I have no success).

It would be great if you could help to solve the problem.

Ralf