Hello,

this is what i have. A detacenter where all my servers are. DC gave me some IP subnets and they are all used up. Now i purchased several public subnets from other datacenters and i want to be able to use those IPs inside 1st datecenter where my servers are. This is already implemented like this but i don't know how to add more subnets from new datacenters. At my primary DC i am using Centos linux which is working as router. In every other DC i also have Centos6 who is router and is connected with GRE tunnel to primary DC. What i figured out from previous configs is that i need to "publish" those IP subnets that new DC gave me over new tunnel but (when GRE interface goes up it publishes subnet to central router) but i am not able to assign any of new IPs at primary DC (not even in virtual interface on linux router - RTNETLINK answers: File exists).

Since i am doing this for the 1st time i am not sure if i am missing anything on the primary DC linux router so any help would be greatly appreciated.

Are you saying that you want to be able to route from the internet , through your "other" datacenters, using a public IP address, to your main datacenter ?