I didn’t know that one and like many great things i learned it from one of my ISP’s.

When you have OpenVZ and an ip from another subnet, you can use it, but you have to make a change in openvz configuration for everything to work fine.

So the fix is:

vi /etc/vz/vz.conf

Find line:

NEIGHBOUR_DEVS=

An make it:

NEIGHBOUR_DEVS=all

And that will fix your problem.