Multiple TCP/IP stack processors on a host. The multiple TCP/IP stack processors are provided independently of TCP/IP stack processors implemented by virtual machines on the host. The TCP/IP stack processors provide multiple different default gateway addresses for use with multiple processes. The default gateway addresses allow a service to communicate across an L3 network. Processes outside of virtual machines that utilize the TCP/IP stack processor on a first host can benefit from using their own gateway, and communicate with their peer process on a second host, regardless of whether the second host is located within the same subnet or a different subnet. The multiple TCP/IP stack processors can use separately allocated resources. Separate TCP/IP stack processors can be provided for each of multiple tenants on the host. Separate loopback interfaces of multiple TCP/IP stack processors can be used to create separate containment for separate sets of processes on a host.