A method and apparatus is described that allow the creation of virtual routing domains in an IP network. These virtual routing domains allow individual networks to be configures so that it appears that its routing domain covers the entire IP address space. A network processing system is used to implement the virtual routing domains and to allow network traffic to cross the individual routing domains. The network processing system is able to use application layer information to allow the crossing of virtual routing domain boundaries. By examining application layer information the network processing system is able to look up customer/user information and use that information to determine destination virtual routing domains and route otherwise unroutable addresses between domains.