Here is my setup:

OpenVZ host node ip 38.100.42.250 (subnet is 38.100.42.248/29)

hosts 38.100.42.249, 250, 251, 253, 254 all work. 

I was assigned, additionally, the following: 

38.105.84.192/28
Subnet Mask: 255.255.255.240
Broadcast: 38.105.84.207
Usable IPs: 38.105.84.193-206

And told to use the same gateway as before.

When I add a new VE with one of the ip adresses in that range, it cannot ping past 38.100.42.250.